Copyright©2017byMichaelHennellKingandMilesAdrianSouthern.Allrightsreserved.

CoverdesignbyDianeMcIntosh.Text Editor: Valley Hennell. Graphic designer: Andrej Klimo. www.andrejklimo.com Cover photo ofplated trout:Our trout servedat theOldFirehouseWineandCocktailBar inDuncan,BC (photocredit:CoryTowriss).Importantgraphic:Adobestock_67829647.Allimagesareauthor-suppliedunlessotherwisenoted.

PrintedinCanada.FirstprintingOctober,2017

Althoughtheauthorsandpublisherhavemadeeveryefforttoensurethattheinformationinthisbookwascorrectatpresstime,theauthorsandpublisherdonotassumeandherebydisclaimanyliabilitytoanypartyfor any loss, damage or disruption caused by the information in this book and by errors or omissions,whethersucherrorsoromissionsresultfromnegligence,accidentoranyothercause.Usersofthisbookarestrongly advised to conduct their own research into costs and income projections, regulatory and legalrequirements,andtherisksassociatedwithstartingafarmoraquaponicbusinessventure.

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LIBRARYANDARCHIVESCANADACATALOGUINGINPUBLICATION

Southern,Adrian,1982-,authorThe aquaponic farmer : a complete guide to building and operating a commercial aquaponic system /AdrianSouthern&WhelmKing.

Includesbibliographicalreferencesandindex.Issuedinprintandelectronicformats.ISBN 978-0-86571-858-6 (softcover).--ISBN 978-1-55092-652-1 (PDF).-- ISBN 978-1-77142-247-5(EPUB)1.Aquaponics.2.Aquaculture.I.King,Whelm,1977-,authorII.Title.

SB126.5.S682017 635’.048 C2017-904850-3

C2017-904851-1

NewSocietyPublishers’mission is to publish books that contribute in fundamentalways to building anecologicallysustainableandjustsociety,andtodosowiththeleastpossibleimpactontheenvironment,in

amannerthatmodelsthisvision.

Contents

ACKNOWLEDGMENTS

PREFACE:AWORLDWITHOUTWEEDS

INTRODUCTION:THESTATEOFTHEWORLD

Chapter1:WhatIsAquaponics?

APrimeronAquaponicsAVeryBriefHistoryofAquaponicsAquaponicEcomimicryAquaponics,PermacultureandSustainabilityAquaponicPlantSystemsDeepWaterCultureSystemsDripTowerSystemsDWCorDripTowers—OurRecommendation

PlantSitesandLightAvailabilityBacterialSurfaceAreaAvailableOxygenFiltrationOurConclusion

BackyardvsCommercialSystems

Chapter2:TheRCASystem

ThePurposeofThisBookAvoidingOurMistakes

ANoteonReadingBeforeBuildingANoteonMetricvsImperialANoteonCurrencyANoteonNorthPropertyConsiderations

ZoningSunExposureCharacteristicsoftheLandAccesstoPowerandWaterPrevailingWindsWasteDisposalLong-termLandRightsLivingOnSite

TheGreenhouseSizeNewvsUsedTypesofCoveringRecommendedFeaturesHeatingtheAirCoolingtheAirHeatingandCoolingtheWaterHeatPumpTheRaincoastAquaponicsGreenhouse

GreenhouseLayoutTroughs

TroughDesignPrinciplesTheRCATroughsRafts

FishTanksFiltrationSystems

MechanicalFiltrationBiologicalFiltrationRCAFiltrationSystemsRadialFlowSeparator(RFS)CombinationFilterBox(CFB)

UltravioletSterilizationSupplementalLightingGerminationChamberSeedlingAreaWater:TheLifebloodoftheFarm

WaterTemperaturepHWaterQualityManagement

AerationPumps

TowerSystemPumpsEffluentTheSump

TheDrainDownEffectWorkbenchCisternPowerConsumption

Chapter3:PrinciplesofSystemDesign

TheGoldenRatioofCold-waterAquaponicsCold-WatervsWarm-WaterAquaponics

UsingtheGoldenRatioStep1Step2ANoteonTowerSystemsAFinalDesignNote

Chapter4:ConstructingtheRCASystem

SitePreparationGreenhouseConstruction

FoundationInstallationArchesInstallationEndwallInstallationCoveringInstallationRollUpSidesInstallation

HangingComponentsInstallationCirculationFansInstallationHeaterInstallationHIDLightInstallation

ElectricalandInternetInstallationInternetInstallation

SumpConstructionSumpConstruction

WasteTankExcavationTroughConstruction

GroundPreparationTroughConstructionSideandMiddleWallConstructionEndwallConstruction

AssemblingtheWallsFinalPlacementoftheTroughs

TroughLinerInstallationTroughPlumbingInstallation

InletplumbingDrainplumbingSidetoSidePlumbing(U-turn)EstimatedPartsListforTroughConstruction

RaftConstructionPaintingtheRafts

SourceWaterInstallationAquacultureSubsystemInstallation

LayoutInstallingtheMainWastePipeInstallingtheFishTanksBuildingtheStandpipeAssemblies(SPAs)InstallingtheRadialFlowSeparatorInstallingtheTankManifoldConnectingtheTankManifoldtotheRadialFlowSeparatorConstructingtheCombinationFilterBox(CFB)InstallingtheMovingBedBioReactor(MBBR)InstallingtheFilterScreensInstallingtheCombinationFilterBoxInstallingtheUndergroundPlumbing(TroughSide)InstallingtheAerationPipe

AerationBlowersInstallationAirStoneInstallation

PumpSidePlumbingInstallation

InstallingtheUVSterilizersInstallingtheUVtoFishTankPlumbingCalculatingtheSystemHeadSelectingthePumps

HeatPumpInstallationCisternInstallationSeedlingTableConstructionWorkbenchConstructionWalk-inCoolerInstallationGerminationChamberConstruction

Chapter5:ToolsoftheTrade

ShadeClothBackupOxygenandPowerMonitoringSystempHControllerDissolvedOxygenMeterWaterTestingKitSeedlingTraysandDomesSubstratesDibblerPlateNetPotsTotesPackagingSaladDryerScalesKnivesandScissorsFishingNetsandTankCovers

CleaningBrushesWashingMachineChestFreezerHotWaterSystemStainlessSteelCounter/SinkConstructingtheWashDownSinkFeedStorage

Chapter6:ManagingtheEcosystem

BacteriaNitrifyingBacteriaMineralizingBacteriaBacteriaandUV

MineralandNutrientContentAmmonia,NitritesandNitratesOtherPlantNutrientsChemicalTestingSampleWaterLocationPlantObservationNutrientRecycling

WaterQualityandManagementpHTwopHManagementMethods:BufferingvsHydroxidespHManagementWaterTemperatureDissolvedOxygen(DO)OptimumWaterQualityParameters

Chapter7:CyclingtheSystem

FillingtheSystemwithWaterCyclingtheSystemTheImportanceofCalciuminCyclingTheFirstCohortofFishTheFirstYearofOperationFullCapacity

Chapter8:RaisingFish

FishSpeciesFeedConversionRatio

FishSourcingRecordKeepingFishTransportFishTemperingandQuarantine

TemperingQuarantine

FishFeedFeedingYourFish

SamplingFeedingTechnique

FishTankRotationTankCleaningandSterilizingFishHealth

HydrogenPeroxideTreatmentSaltBathTreatmentLabAnalysis

PurgingBeforeHarvestHarvestingFish

Chapter9:PlantProduction

PlantsSelectionThePlantsWeProduceatRCA

SeedsTheGrowthCycle

DirectSeedingMulti-stageProduction

PlantingSeedsGerminationSeedlings

TransplantingintotheTroughsRaftPlacementandRotationTransplantScheduleThinningandSpacingPlantsMaturingPlantsPlantInspectionWateringintheGreenhouse

Harvest,PackagingandStorageHarvestingMethodsWashingPlantsSaladMixesPortioningPackaging

HarvestCleanUpTheProductionCycleNutrientDeficiencies

NitrogenCalciumandPotassium

IronHighAmmonia

Chapter10:PlantDiseasesandPests

PythiumPowderyMildewFungusGnatsAphidsCabbageLoopersEarwigsPillBugsSlugsBirdsRatsMinkandMartenBears

PlantDiseaseandPestManagementCulturalControlsEnvironmentalControlsHeating/VentilationCycleStickyTrapsPredatoryInsectsUsingPesticideandFungicideSpraysLethalConcentrationCalculationRe-entryIntervalPersonalProtectiveEquipment(PPE)Foggers

Chapter11:StandardOperatingProceduresandProtocols

DailyLogWeeklyTasks

NotesforPhase3WeeklySeedingChartCropLogFishSampleLogCohortLogMonthlyandSeasonalTasks

ReplacingUVBulbsLogsandProtocols

Chapter12:MarketingandSales

AquaponicAdvantagesYearRoundProductionEthicalPlantsEthicalFishAquaponicsisSexy

PotentialMarketsFarmersMarketsRestaurantsandRetailStoresWholesaleDistributorsFarmGateSalesMarketComparisonTheRCASalesModel

PromotingYourFarm

Chapter13:CreatingaBusinessPlan

ConstructionCostsPropertyAcquisition

LaborCostsSitePreparationGreenhousePowerListofInitialCosts

OngoingOperationalCostsListofOngoingOperationCosts

IncomeEstimatesIncomeEstimateTable

FINALTHOUGHTS

RESOURCES

SOURCES

GLOSSARY

Acronyms

INDEX

ABOUTTHEAUTHORS

ANOTEABOUTTHEPUBLISHER

Toallfarmers

F

Acknowledgments

IRSTANDFOREMOST,wethankourprimarycollaboratorsonthisproject:ourmothers and editors, Valley Hennell and Kerrie Talbot; Andrej Klimo,

graphic designer;Michael Timmons, content reviewer; andRobWest and thewholeNewSocietyteam.

We thank the pioneers who paved and continue to pave the way: MarkMcMurtry and James Rakocy for their foundational work in aquaponics;Michael Timmons and James Ebeling for their voluminous research intorecirculatingaquacultureandaquaponics;andnumerousotherfarmerswhohavesharedinformationandethicswithus,directlyorindirectly.

AdrianSouthern:IwouldliketothankmyfriendKirstiforplantingtheveryfirstseed that eventually grew into this book, andmy entire family (especiallymywifeKim)for theirongoingsupportduring thisproject.Also,Steve,JanetandAmandaatTasteofB.C.forassistingmeinallthingsaquacultureandansweringmyendlessquestions.

I

PrefaceAWorldWithoutWeeds

TALLSTARTEDWITHAWEED.Itwasn’tparticularlydifferentthanitsnumerouskin.Itwasjustanordinaryweed,nestledinmyrowsofneatlyplantedlettuce,

mockingme.Itwasbothbenignandthebaneofmyexistence,thecauseofthequite literal pain inmy ass. I had been SPIN farming for the past two years,usingtwoofmyneighbors’backyardstoproduceavarietyofvegetablesthatIsold at local farmersmarkets.Theworkwas constant and intense.Convertingcityyardsintosmallfertilefarmswaslaborious,andmanagingseveralofthemwasadailystruggle.Allworkconsidered, Icalculated Iwasearningabout$2perhour.Mybodywasaching,Iwasjustmanagingtokeepmycropsreasonablyhealthy,andthereIstood,lookingattheweedunderaboilingsun—theweedthathadn’tbeentherejustafewdaysagowhenIhadlastspenthoursweedingthis plot.And itwasn’t alone.Therewas a veritable army of them.As I bentovertodiginyetagain,Iknewtherehadtobeabetterway.

Thereis.In2009afriendofminewhowasenrolledintheFisheriesandAquaculture

programatVancouverIslandUniversityinNanaimo,whereIhadlivedforsomeyears,invitedmetotakeatourofthefacility.Theschoolhadrecentlysetupasmall aquaponics system as a demo for the concept. It was a moment ofepiphany thatwould changemy life. Iwas immediately hooked.Raising bothplantsandfish.Sustainably.Allyearround.Withwaterusecutby90%ormore.Withouttheneedforarableland.

With.No.Weeds.Aftervisiting theuniversity, Iknewmydaysasanurban soil farmerwere

over. For the next three years I voraciously researched aquaponics. I readeverythingIcouldfindonthesubject.Idesignedandbuiltnumerousbackyardsystems.Iexperimentedandtested.IsucceededandIfailed.Ibecamemoreandmoreconvincedthataquaponicshasavitalplaceinthefutureoffarming.

In2012,IpurchasedapropertyintherollinghillsoftheCowichanValleyon

southernVancouverIsland,BritishColumbia,withtheintentionofestablishinga commercial aquaponic farm. I approachedmygood friend,WhelmKing, anentrepreneurandbusinessmanager,toassistme.Together,wecreatedRaincoastAquaponics(RCA).

Todaywegrowawidevarietyofvegetablesandraiserainbowtrout inour36′×80′ greenhouse. Annually, we produce approximately 30,000 heads ofvibrant,delicious lettuce(orequivalentothercrops)and750kgof tenderpinktrout.Wealsoraisepigsalmostentirelyoncompostandproducefishfertilizerthatwebottleandselltolocalfarmersandgardeners.

Aworldwithoutweedsisnotpossible.Afarmwithoutweedsis.

AdrianSouthernOctober2016

A

IntroductionTheStateoftheWorld

S YOU HAVE JUST STARTED READING a book on aquaponic farming, we’regoing tomake somebasic assumptions.We’re going to assume that you

understand the urgency of climate change and are familiarwith such terms as“peak oil” and “sustainability” and “localization.”We assume that you don’tneed convincing that industrial agriculture is, by its very nature, a system ofincreasing costs and decreasing returns which turns arable land, one ofhumanity’s greatest resources, into sterile landscapes requiring constantchemicalfertilization.Thefertilizersthemselvesarederivedfromfossilfuels,adwindlingandpollutingresource.

Industrialagriculturehasdisruptedthenaturalmethodsoffarmingthathavesustainedhumansformillennia.Itproduceslow-qualityfoodheavilydepletedoftheessentialelementsnecessaryforhumanhealth.Fertilelandbecomesbarren,humanhealthdeteriorates,andthewholesystemrequiresvastinfrastructurestogrow,store,move,storeagain,moveagain,storeyetagainandsoon,beforeitisfinally sold tous inall itsnutrition-lackingglory.Thewhole system is fragileandrigid,everylinkinthechainessentialandrequiringlargeinputs.Ifevenonelinkbreaks,alleffortsarespoiledandallfoodwasted.Inpermacultureterms,thesystemlacksanysemblanceofredundancy.

Industrialagricultureisinherentlyunsustainable,andthesystemisbreakingdown. Global food supply is increasingly unstable with food prices sharplyincreasing inmany parts of theworld.Here inNorthAmerica this reality hasbeenmostlyhiddenduetogovernmentsubsidies.

Once in a lifetime droughts are now common. Pollinator colonies arecollapsing. Super weeds, resistant even to the poisons that created them, arerampant.Theindustrialpromiseoflowfoodpricesisbeingrevealedastheshamitalwayswas.

We continue to rely on industrial agriculture at our own peril. Change isrequired.

Insummarizingourfoodsysteminthismanner,weassumewe’repreachingto the choir. We assume that you want to be part of the solution — themovement to reclaim our food systems — for the sake of both healthyecosystemsandourownhealth,andtoallowfuturegenerationstheopportunitytosurviveifnotthrive.

The growingmovement to counteract the ills of industrial agriculture andglobalizationisrobustandfilledwithvitalityandenergy.Itisamovementofthepeople forboth thepeople and the land. It is amovementdesigned to endure.Thecentraltenetislocalization.

Producelocally.Buylocally.Uselocally.Supportlocally.Belocal.Relocalization of food production can take two primary forms: moving

backwardormovingforward.Movingbackwardmeansusingthetime-testedmethodsthathavesustained

humans since agriculture was invented. It is the revitalization of traditional,small, labor-intensive organic farms. It is nurturing the land and managingnatural ecosystems, creating soil teemingwithmicroorganisms and farming inharmonywithandwithinthelimitsoflocalenvironments.Itisanancientsystemwhoseflagmightbestberepresentedasashovelandcompostpile.

Moving forward is using technological advancements and scientificknowledgetoproducefoodoutsideofnaturalecosystems,virtuallyanywhereitisneeded. It isusing resources and ingenuity to createourownecosystems toproducefoodwithalmostnoenvironmentalimpact,inalmostanyclimate.Itisbuildingthecapacitytoproducefoodlocallyinallseasonswithhighlyefficientlaborandwateruse.Webelieveaquaponicsismovingforward.

We are advocates for bothmoving backward and forward. Thesemethodsarenotincompetition:bothhaveadvantagesanddisadvantagesandarevitaltofoodsustainability.Wehavetheutmostrespectfortraditionalfarmers.Wehavechosentobepioneers.Weareaquaponicfarmers.Joinus!

T

WhatIsAquaponics?

APrimeronAquaponicsHE WORD “AQUAPONICS” was coined in the 1970s as a combination of thewords “aquaculture” and “hydroponics.”Aquaculture is the cultivation of

aquaticanimalsandplantsinnaturalorcontrolledenvironments.Hydroponicsisthegrowingofplantswithoutsoil,usingwater tocarrythenutrients.Theterm“aquaponics” was created to designate the raising of fish and plants in oneinterconnectedsoillesssystem.

Aquaponicscansolvethemajorproblemsofbothfreshwateraquacultureandhydroponics.

Themajorprobleminland-basedaquacultureisthatfishwasteinthewatercreates continuously elevating levels of ammonia. If left unchecked, this toxicelementwillrapidlykillthefish.Theaquacultureindustrytypicallyusesoneorbothoftwooptionstoresolvethisproblem:aconstantsupplyoffreshwatertoreplacethetoxicwaterand/orexpensivefiltrationsystems.Neitherisideal.Theformernotonlyusesvoluminousquantitiesofourpreciousfreshwaterbutalsocreates equally large quantities of high-ammonia water that is toxic to anynatural ecosystem. The latter is simply very expensive. The high cost isespecially pertinent to smaller commercial operations as most filtration unitsonlymakefinancialsenseatlargeeconomiesofscale.

Fishfarmsinnaturalbodiesofwater,oftencalled“opennetpens,”arerifewithproblems,notablytheirpotentialfornegativelyimpactingwildfishstocks.Wedonotsupportsuchfarms,andtheyarenotconsideredinthisbook.

Themajor problem in hydroponics is the ongoing need for large inputs offertilizers.Asoillessproductionsystemmeansalltheminerals—allthefood—requiredbytheplantsmustbecontinuallyadded.Fertilizersareexpensive,andthe vast majority are fossil-fuel derived, often referred to as “chemical”fertilizers.Availableorganicfertilizersarenotcommonlyusedbecausetheyarelesswatersoluble,thusmorelikelytocauseproblemsandcanbeseveraltimesmore expensive than their chemical counterparts. Hydroponic farms are oftenalso a major water consumer as many use a drain-to-waste system. Evenhydroponic farms that recirculate water must drain and replace their waterregularlyastheydonothostalivingecosystemthatbalancesitself.

Theaquaponiccycle.

By combining fish and plants into one system, aquaponics can solve theprimary problems of both aquaculture and hydroponics. Fishwaste provides anear-perfectplantfoodandissomeofthemostprizedfertilizerintheworld.Theplants, using the minerals created from the waste, do most of the work ofcleaningthewaterforthefish.

The fish feed the plants. The plants clean the water. The symbiosis is aslogicalasitiseffective.

The third living component in aquaponics is bacteria. The whole systemhosts specific types of bacteria that serve two roles. One family detoxifiesammonia in the effluent by converting it into nitrates. Another familymineralizesorganicmaterial(primarilyfishfecesanduneatenfeed)bybreakingitdownintoitselementalconstituents,whichareusablebyplants.Withoutthisvital conversion in a closed system, both fish and plants would rapidly die.Establishing the bacterial cultures and monitoring their health is one of mostimportanttasksofanaquaponicfarmer.WecoverthistopicindepthinChapter6.

AVeryBriefHistoryofAquaponicsAlthough modern aquaponics is only a few decades old, the concept ofcombiningfishfarmingandplantproductionformutualbenefitisthousandsofyearsold.

Sinceancienttimes,fishhavebeenraisedinfloodedricepaddiesinChina.Thefishandriceareharvestedat thesametimeannually,andthetechniqueisstill used today. Ducks, sometimes in cages, were kept on the edges of fishpondssotheirexcrementcouldbeusedtofeedthefish.

TheAztecshadadvancedtechniquesofaquaponicfarmingcalledchinampasthatinvolvedcreatingislandsandcanalstoraisebothfishandplantsinasystemof sediments that never required manual watering, achieving up to sevenharvestsperyearforcertainplants.

In 1969, John and Nancy Todd andWilliamMcLarney founded the NewAlchemy Institute in Cape Cod, Massachusetts, and created a small, self-sufficient farmmodulewithin a dwelling (the “Ark”) to provide for the year-round needs of a family of four using holistic methods to provide fish,vegetables and shelter. In themid1980s, agraduate student atNorthCarolinaUniversity, Mark McMurtry, and Professor Doug Sanders created the firstknownclosedloopaquaponicsystem.Theyusedtheeffluentfromfishtowaterand feed tomatoesandcucumbers in sandgrowbedsviaa trickle system.Thesandalsofunctionedasthebiofilterofthesystem.Thewaterpercolatedthroughthe sandand recirculatedback to the fish tanks.McMurtry andSanders’ earlyresearchunderpinsmuchofthemodernscienceofaquaponics.

The biggest leap came from Dr. James Rakocy at the University of theVirginIslands.Fromaround1980through2010,hewasResearchProfessorofAquaculture and Director of the Agricultural Experiment Station, where hedirectedvoluminous researchon tilapia inwarm-wateraquaponicsystems.Hisresearchon theconservationandreuseofwaterandnutrientrecyclingremainsthegreatestbodyofmodernworkonaquaponics.Thoughittookmanyyearstodevelop,byaround1999Dr.Rakocy’ssystemhadproven itself tobe reliable,robust and productive. His developments are used today from home tocommercial-scaleaquaponics.

Our work has been primarily developing systems and protocols that haveallowedustomodifytheworkofsuchvisionariesasMcMurtryandRakocytocold-waterproduction,bettersuitedtocolderenvironments.

AquaponicEcomimicryEcomimicry is the design and production of structures and systems that aremodelled on biological entities and processes. Aquaponic systems aremanufacturedenvironments thatattempt to replicateacomplexnaturalsystem.Everycomponentandprocessinanaquaponicsystemhasanaturalcounterpart.

Imagineafreshwaterecosystem.Atahighelevationisalakeinwhichfishconstantlyproducewasteintheformofammoniaandfeces.Ariverflowsfromthelakecarryingthesewastes.Alongthebottomoftheriverarelayersofgraveland sand which are home to various bacteria and invertebrate detritivores(worms,insects,crayfish,etc.)

Aswaste-ladenwaterflowsdowntheriver,fecessinktothebottomandaretrapped in the gravel where it is eaten and broken down by detritivores andbacteria, converting it into elemental constituents and minerals. Ammonia (atoxicformofnitrogen)inthewaterisnitrifiedintonitrates.Withoutbacteriaanddetritivores,thewastewouldeventuallybuildtotoxiclevels.

Therivercontinuesdownstreamtolowerelevationsandeventuallymeetsawide, flatwetlandarea.Here it slowsand spreadsout, depositingmineral-richsedimentswherevegetationabounds.

Afterbeingfilteredof itsnutrientsandsediments in thewetland, thewaterendsitsdownhill journeyintheocean.Butthis isnot itsend.Evaporationand

evapotranspirationfromplantscombinetoformclouds,andtheirmoisturefallsas rain, which collects in large bodies of water such as lakes, and the cyclerepeats.

Allthesenaturalprocessesarefoundinanaquaponicsystem:thefishtanksarethecounterparttothelake,thefiltrationsystemsarethegravelintheriver,and thehydroponic subsystem is thewetland.Themainwaterpump serves ascloudsbyreturningthewatertothehighpointinthesystem:thetanks.

As we are mimicking a natural ecosystem, many challenges found in anaquaponicsystemarealsofoundinnature.Naturehadbillionsofyearstoevolvesolutionswhichmaybereplicatedinaquaponicfarmsbyimitatingnature.

Aquaponics,PermacultureandSustainabilityWebelieveaquaponicsisasystemofpermaculture.Allthreetenetsandtwelveprinciplesofpermaculturedesignarerealizedwithinanaquaponicsystem,fromconceptionanddesigntooperation.

One of the core tenets of permaculture is the “return of surplus”which ismaximizing the efficient use of resources and eliminatingwaste.Often,wastecanbeeliminatedsimplyby recognizing itasa resourceandusing rather thandiscardingit.Anaquaponicsystemhasthistenetatitscore,asobservedintherelationshipbetweenfish,bacteriaandplants.

Aquaponicshasinputsandoutputs.Whenpermaculturedesignprinciplesareapplied, the inputs are minimized and used efficiently and the outputs arerecycled back into the system as inputs.AtRaincoastAquaponics,we extractfivedifferentuses fromeverykilogramof fish feedand threeuses fromeveryliterofwater.

Thefishfeed isused to raise fish(1),which in turnfeedplants (2)via thebacteria.Theresultingfishwasteiscapturedandconvertedtoafertilizerproduct(3),andthecropresidue(compost)isfedtopigsandconvertedintobacon(4).Pigwasteiscompostedandusedtobuildsoilforgrowingfieldcrops(5).

Waterisfirstusedtopurgefishpriortoharvest(1),andthenusedtotopupthemainsystem(2).Theeffluentflushedfromthesystemisusedtowaterfieldcrops(3)aftermostofthefishwastehasbeenextracted.

AquaponicPlantSystemsThereareseveralcommonlyusedaquaponicssystemswhosenamesrefertothemethodofplantproduction.Systemsofraisingfishareallverysimilar,thusnotconsideredinnamingaquaponicsystems.Inallsystems,twobasicfunctionsarefound:wateriscycledbetweenthefishandtheplants,andbacteriaconvertfishwastetobeneficialminerals.

Thefourmostcommonlyusedaquaponicplantproductionsystemsare:DeepWaterCulture,DripTowers,NutrientFilmTechniqueandMediaBed.

Deep Water Culture (DWC): water flows down long troughs of water,typicallyabout12″deep,likeaslow-movingstream.Rafts,typicallymadefromstyrofoam,floatonthewaterwithapatternofholescutintothem.Smallopen-bottompots,callednetpotsorslitpots,fitintotheholes.Plantsaresupportedinthepotsbyavarietyofdifferentmediums.Therootsoftheplantsaresuspendedandgrowinthemovingwater.

DWCtroughswithfloatingpolystyrenerafts.

DripTowersaretubes,typicallymadefromPVC,witheitherholesoraslitrunning the length of the tube on one side, suspended vertically in rows. Thetowers contain a growing media into which plant roots grow. Water iscontinuouslyfed into the topofeach tubeandcollectedat thebottomtocyclethroughthesystemagain.

NutrientFilmTechnique (NFT) alsouses tubes, typicallyPVC,withholeson one side. Whereas drip towers are suspended vertically, NFT tubes aremountedhorizontallyonaslightanglewiththeholesfacingupwards.Plantsaregrowninsmallnetpotsinsertedintotheholesinthetubes.Water,continuouslyfedintothehighsideofthetubes,flowsdowninathinfilmcontactingtherootsandiscollectedatthelowsidetocyclethroughthesystemagain.

HealthyrootsunderaDWCraft.

MediaBed isa typeof floodanddrainproductionwithnumerouspossibleconfigurations. In all configurations, watertight growing areas are flooded atregular intervals by pumps then drain back to cycle through the system. Thegrowing areas are filled with a pebble-like medium, often expanded clayaggregate but sometimes simply gravel. Plant roots grow throughout themedium.

While thereareprosandcons toeachsystem, inouropinion theonly twosystems worth considering for a commercial operation are DWC and driptowers.Mediabedsystemsarenotpracticalduetothemaintenancerequiredtoremove trappedsolidsand thehigher riskof rapidcropfailure ifamechanicalproblemoccurs.NFTsystemsarewidelyusedinhydroponicproductionbutareinferiortodriptowersandDWCforbothbacteriacolonizationandspaceusage.WestronglysuggestDWCordriptowersforcommercialproduction.ThisbookisbasedaroundaDWCsystem.

ZipGrow™Towers.

CREDIT:BRIGHTAGROTECH

•••••

ZipGrow™Towerarray.

CREDIT:BRIGHTAGROTECH

DeepWaterCultureSystemsTheprimaryadvantagesofDWCare:

LessexpensivetoconstructEvenlightdistributionIncreasedthermalmassduetothelargevolumeofwaterinthesystemAbilitytoselectivelymoveindividualplantsforthinningandspacingGreateroptionsforpestcontrol

Lessexpensive:

Cost isby far thebiggestadvantageofDWC.Fora120′×36′greenhouse,youcan expect to spend at least US$50,000 more to install a drip tower systemcomparedtoDWC.

Lightdistribution:

AllplantsinaDWCsystemhaverelativelyequalaccesstolight.Astheyareallon one horizontal plane, they are potentially only partially shaded by their

immediateneighbors.Incontrast,theverticaldesignofatowersystemmeansanincreasedpotentialforshading,particularlyforthelowerplantsandallthemoreso when using supplemental light that will not penetrate as effectively assunlight.

Thermalmass:

DWCsystems contain about three timesmorewater than a drip tower systemduetothevolumeofthetroughs.ADWCsystemina120′greenhousewillhaveapproximately 66,000 liters. A tower system will have approximately⅓ thisvolume(18,000L).Theadditionalwaterservesas thermalmasswhichbufferstemperatureduringcoldandhotperiods,anddoessowhere it isneededmost,immediatelyaroundtheplants.

Thinningandspacing:

Rafts have both advantages and disadvantages. A primary advantage is thatindividual plants can easily be removed from the system or relocated whichallowsyoutostartplantscloselyspacedandspreadthemoutastheygrow.

Pestcontrol:

Itisalsoeasytoseeandremoveproblemplantssuchasthosewithpests,moldormildew.Additionally,plants inaDWCcanbedirectlywashedwithsystemwaterwithoutlosingthewater.Thisisahighlyeffectivemethodformaintainingplanthealthandisnotpossibleinatowersystemwithoutlosingthewaterused.

Thedisadvantagetoraftsisthattheyareneargroundlevel(approximately1′aboveground),thustheworkinvolvesregularlybendingover.Fullyloadedraftscanweigh30–40lbs.andcanbeawkwardtomove, thoughcarryingraftswithmatureplantsoverlongdistancesisnotneededorrecommendedinoursystemasmostharvestingtakesplaceatthetroughs.

DripTowerSystemsAllmentions of towers or the performance and layout of towers in this bookrefer toZipGrow™TowersbyBrightAgrotech.Theseare theonly towerswespecificallyrecommend.

Theprimaryadvantagesofdriptowersare:

••

••

PotentiallyincreasednumbersofplantspersquarefeetofgrowingspaceIncreased nitrifying capacity, as the tower media has a large BacterialSurfaceAreaIncreasedoxygenavailabilitytoplantsduetothehighporosityofthemediaPotentiallyeasierworkflow

Increasedplantsites:

Income fromanaquaponic system ismostlymade fromplants,not fish, soanincreaseinplantsitesdirectlycorrespondstoanincreaseinpotentialincome.

IncreasedBacterialSurfaceArea(BSA):

BSAistheareawithinasystemthatnitrifyingbacteriacancolonize.LargeBSAincreases are only found in matrix-based tower systems such as ZipGrow™Towers. The superior BSA due to themedia used in ZipGrow™Towers is asubstantialadvantage.A5′driptowercanprovideapproximately150squarefeetof BSA in the tower media. DWC without additional biofiltration providesapproximately6squarefeetofBSAinthesamespace.

Increasedoxygenavailability:

InDWCsystems,plantrootsaresubmergedunderwaterwhichlimitsthetypesof plants suited to the system. Supplemental oxygen must be added by anaerator, and its availability to the plants is limited by the oxygen carryingcapacityofwaterwhichisapproximately10ppmat15°C.

With drip towers, roots grow into a porousmedia throughwhichwater isslowly trickled. Rather than being submerged in water, roots are directlyexposedtotheairandthustheoxygenintheairisavailabletotheplants.Towersystems are self-aerating due to the high air/water exchange as water tricklesthroughthemedia.

Easierworkflow:

Theworkflowinbothsystemsissimpleoncepracticed.Theprimarydifferenceis that inDWC all the plants are located at the same height (about 1′ off theground).Inatowersystemusing5′towers,plantsrangeinheightfromabout1′to6′andthetowerscanbeeasilycarriedaround.

DWCorDripTowers—OurRecommendationItisimportanttounderstandthatifproperlydesigned,constructedandoperated,both DWC and tower systems will produce beautiful plants and high-qualityfish.WeuseDWCsoadmitourbias.Weacknowledge that towershavesomedistinctadvantagesandrecommendthemasanexcellentproductionsystem,butoverallwebelieveDWCissuperior.

PlantSitesandLightAvailabilityWhiledrip towershaveanadvantage inplant sites, thedifferencebetween thetwosystemsisnotasgreatasitmightseem.A120′×36′greenhousewith86′ofplantproductionareahasthepotentialfor8,000plantsitesusing5′driptowersand6,192harvestableplantsitesusingDWC(seeChapter2).

Theincreasedplantcapacityfortowers(8,000vs6,192)wouldseemlikeagame changer, but we do not agree. The 8,000 number is based on therecommendedspacingforZipGrow™Towersof20″betweenplantcenterssidetosideand16″centersbacktofront,with36″-walkwaysbetweenarrays.

Our concern is that, in a temperate latitude or colder, light will notsufficiently reach the lowest plants. Our concern is doubled during the 4–6monthsayearwhenlightingsupplementationisrequired.Incontrast,inaDWCsystemtheplantsareallatonehorizontallevel,thusaccesstolightisvirtuallyidentical throughout the greenhouse and light supplementation is evenlydistributed.Sowhiletowershaveatheoreticaladvantageinplantsites,wefeelthe limitations on light distribution greatly reduces if not eliminates thissupposedadvantage.

Wealsonotethattohouse8,000plantsitesrequires4arrayswith5rowsoftowersper array in a36′-widegreenhouse.Thismeans thewalkways areonly28″whichwillfurtherreducelightpenetrationandcreatesatightworkingarea.Note that this spacing leaves walkways that are narrower than the 36″recommended by ZipGrow™ for light penetration and working space. If youreduce to 3 arrays, you canwiden thewalkways to 48″which increases lightpenetrationbutalsoreducesthetotalplantsitesto6,120.

Another option is to use 3 arrayswith 6 rows per array instead of 5.Thisallows for 7,152 plant sites and 35″ walkways with rows 18″ on center. The

downside of this option is that itmay be problematic for the plant productionschedule,which involves rotating towers throughan array asplantsmature.A40′-wide greenhouse will help solve this problem by increasing walkways toabout38″with4towerarrays.

Ultimately,wefeelthatanygaininplantsitesinatowersystemiscounteredbya lackofequal light,or thatprovidingequal lightmeansvirtually thesamenumberofplantssitesasinDWC.

BacterialSurfaceAreaThegreatlyincreasedBSAofatowersystemthatusesamatrixmediaisarealadvantage. However, it is important to understand that the bacterial colonycapacity of DWC is more than sufficient to raise healthy fish and excellentplants. Additionally, BSA can be increased in any system with the use of abiofiltermodule,aswehavedoneinourdesign.

From a functional standpoint, the extra bacterial capacity of drip towersmeansthatyouwillhavemorewiggleroomintermsofthetotalfishloadinthesystem and you can be less precisewith the quantity of fish feed (excess fishfeedalsobreaksdownintoammonia).Inotherwords,theprimaryadvantageoftheincreasedBSAisnotincreasedplantproduction,whichiswhereyourprofitscomefrom,butinincreasedfishcapacityandinneedingtobelessprecisewithhowyourunyoursystem.NotethattheincreasedBSAonlyappliestomatrix-mediabasedsystemssuchasZipGrow™.

AvailableOxygenWhilegreatlyincreasedoxygenisarealadvantagefordriptowers, theoxygenlevelsinDWCaremorethansufficienttoraisemosttypesofplantsrapidly.Sowhile theadvantage isclearly todrip towers inoxygencapacity,both systemswillexcelifdesignedandrunproperly.

Itshouldalsobenotedthatthesamecharacteristicsthatallowtowerstobeself-aeratingalsocausethewatertogainorloseheatquicklyduetoitsexposureto the air. Hence tower systems have much less thermal stability than DWCsystems.

Filtration

Themediausedintowersactasthousandsoffilters.Thefiltrationcapacityinatowersystemisunparalleled.Thatsaid,aswithmostothertoweradvantages,thefiltrationinourDWCdesignismorethansufficienttoproduceatlevelsofhighefficiencyinvolumeoverthelongrun.Theadvantageistotowers,butitislessimportantthanitseems.

OurConclusionAllthingsconsidered,wefeeltheadvantagesofatowersystemareconsiderablyless than they first appearwhen comparedwith ourDWC system.When youfactorintheadvantagesofDWC,notablythelowercostofconstructionandtheconsistencyoflightavailability,wefeelDWCisthesuperiorsystem.

To be clear, we approve of and recommend tower systems such asZipGrow™foraquaponicproduction.Theyhavebeenproventoexcel.Wedo,however,feelthebenefitscomparedwithawell-designedDWCsystemarelessthantowerproponentsclaimandthatthebenefitsdonotjustifytheconsiderableextracost,unlesscostisnotaconcernforyou.ThoughthisbookisbasedonaDWC design, we will at appropriate times throughout convey informationspecifictotowersystems.

BackyardvsCommercialSystemsBackyard systems typically cannot be scaled up to commercial systems of thesize discussed in this book.We have constructed numerous backyard systemsovertheyears.Theyareafunprojectthatcanbeveryproductive,andwehighlyrecommendthemtoeveryonewiththeavailablespaceandbasicbuildingskills.Thedifferences between a backyard system thatmight contain as little as 100litersofwaterversusa120′DWCsystem thatcontains600 times thatvolumeareconsiderable.

In a small system that might occupy less than 10 square feet, mostcomponents can bemade quite simply or easily sourced at the local hardwarestore.Problemsinthesystemsuchasleaksareeasytosee,easytofix,andtherepercussionsofafailurearesmall.

In a commercial system that will likely cost hundreds of thousands ofdollars,whereleaksmightnotbevisibleasmuchofthewaterpipeisburied,and

where problems can lead to losses ofwhole fish cohorts or plant cropsworthmanythousandsofdollars,thedesignofthesystemhastobecommensuratetothe risk.Additionally, the scale of a commercial system requires entirely newcomponents, suchasa largeparticle filter (weuseaRadialFlowSeparator—seeChapter2),UVsterilizersandawastecollectionsystem.

While all aquaponic systems share the same basic parameters such as thecyclingofwaterandthefish-plantratio(see“TheGoldenRatio”inChapter3),thedesignofcommercialsystemsisdifferentfrombackyardsystems.

I

TheRCASystem

N THIS CHAPTER we dive into the practical aspects of aquaponic systems ingeneral and our system specifically. This chapter introduces all the major

elementsofanaquaponicsystem,includingtheproperty;thegreenhouseandthemajorcomponents;watermanagement;andtheliveentitiesinthesystem:fish,plants and bacteria. This is the most important chapter to read to gain anunderstandingofaquaponicsandofoursystemspecifically.

ThePurposeofThisBookWhilewehavemadeassumptionsaboutyourunderstandingof thestateof theworld,wemakenosuchassumptionsaboutyourknowledgeofaquaponics.Weintendthisbooktobesufficientforsomeonewhohasneverheardofaquaponicstounderstandallitsprimaryelements,fromthesciencebehindthesystemtothenutsandboltsofsettingupandoperatingacommercialaquaponicfarm.

WefarminsouthwesternBritishColumbia,onVancouverIslandclosetothePacificOcean.Ourfarmisinan8Ahardinesszone.Thisbookisrecommendedforaquaponicfarmsintemperateregionsorcooler.

Muchof our designworkhas been the adaptationof theUniversity of theVirgin Islands tropical system to work efficiently and sustainably in colderregions.Theprimarydifferencesareoperatingatcoolerwatertemperaturesandusinglocallyadaptedfishspeciesaswellasappropriateplantvarieties.

Thereareseveralplantproductionmethodsthatarepossibleinanaquaponicfarm. This book is based around a DeepWater Culture (DWC) system, with

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someauxiliaryguidancefortower-basedsystems.This book is also designed around building the entire aquaponic system

withinonegreenhouse.Alternatively,youcanbuildaseparatebuildingtohousetheaquaculturesubsystem.Ifyouoptforaseparateaquaculturebuilding,allthecoredesignprinciples andworkprocesses apply,but the layout and in-groundplumbingwillchange.

Inourexperience,theminimumsizeofgreenhousethatshouldbeconsideredforacommercialoperationis120′longby36′wide.Thissizehasthecapacitytogenerate an excellent return on investment yet can be easily operated by 1–3people at less than 40 hours combined farmingwork perweek (not includingsales,marketingandadministration).Wehavewrittenthisbookaroundthissizeof greenhouse though the formulas and design principles can be scaled up tosystemsmanytimeslarger.

Manyofthedesignprinciplesarenotrelevantorrecommendedforbackyardorhome-basedsystems.For those interested insmallnon-commercialsystems,we strongly recommend Sylvia Bernstein’s excellent book AquaponicGardening(NewSocietyPublishers,2011).

Whilenumeroustypesofplantsthriveinanaquaponicsystem,theplantweuse throughout the book is head lettuce. Using head lettuce as a unit ofproductionhasnumerousadvantagesforbothdesignandbusinessplanning:

ItsproductiontimeisdefinableIttakesaspecificsizeofareatogrowatdifferentstagesofproductionSalesaremeasuredinunits,notweightPriceestimatesareeasytoestablishbasedondifferentsalesoutlets

In other words, head lettuce allows us to easily play with all the keyvariablestodeterminethegrowingprocessandsalespotential.Whenwereferto“plantsites” throughout thebook, theyaresizedforheadlettucebutareeasilyadaptabletomostplants.

Thisbook isalsobasedaround the raisingof rainbow trout.Trouthaveanexcellent feed conversion ratio, are typically easy to source as fingerlings andare highly marketable. While other cold-water species can be raised in thesystem if desired, you should do additional research in advance to confirmsuitability.Notably,someotherspecies thatareconsideredcold-water,suchas

channel catfish or sturgeon, may prove to be advantageous in cold-wateraquaponicsystemsthoughtheyhavenotyetbeentestedbyus.

Insummary,ifyoubuildanaquaponicfarmbasedonthedesigninthisbook,youwillbebuildingacold-wateraquaponicfacilityinone120′greenhousethathousesallproductionsystems(excepttheGerminationChamber),thatiscapableof producing up to 80,000 heads of lettuce per year in aDeepWaterCulture(DWC)system,raising750rainbowtroutperyeartoapproximately1kgeach,andthatcanbeoperatedby1–3peopleworkinglessthan40hourscombinedperweek.

AvoidingOurMistakesBy following the system laidout in thisbook,youwillbeavoidingnumerousproblemsthatcomewithdesigningyourownsystem.Youwillbebypassingthemanymistakesandsystemidiosyncrasiesthatweencounteredandovercameincreating the systempresentedhere.For example, over the first 18months,welost four cohorts of fish for four different reasons, each of which led toimprovements and innovations. Itwas a frustrating beginning thatwe hope tohelpyoutoavoid.

One loss was due to excess ammonia in the initial cycling, due to ourbiofilter not being fully active because of a lackof calcium in thewater.Oneloss was due to fish pathogens and convinced us of the importance of UVsterilizationandfishtreatmentmethodssuchassaltbaths.Onelosswasduetoapoweroutageandledtoourbackupoxygensystem.Andonelosswasduetoawayward frog entering our sump and seizing up the single pumpwe initiallyused.Thatfrogledtoourtwo-pumpdesignandtheuseofamonitoringsystem.

Thesystemsinthisbookaretheresultofcountlesslessonslearnedthehardway, minor and major tweaks, and vast amounts of research and innovation.They also incorporate commercial aquaculture design and components incontrastwith the“do-it-yourself”mentality that iscommoninaquaponics.Theresultingdesignuseswidelyavailable,mostly low-techequipment in a systemthatisproven,predictableandhigh-performance.

ANoteonReadingBeforeBuildingBeforeseriouslyconsideringconstructinganaquaponicsystem,wesuggestyoureadthroughthisentirebook.Whileitislaidoutinalogicalformat,fromearlysiteconsiderations throughmarketingofproducts,youshouldbe familiarwiththetotalityoftheinformationbeforeproceedingtobreakgroundandinvestinafacility.

Noteaswellthatourfarmisaprototype.Someoftheimagespresentedareslightlydifferent than thedesign in thisbookbutare shownfordemonstrationpurposes.Followourinstructionsanddiagramsclosely.

ANoteonMetricvsImperialAll construction measurements throughout the book, including pipes forplumbing,areimperial(inchesandfeet).ConstructioninNorthAmericaisstillgenerallymeasuredimperially.

All aquaculturemeasurements throughout the book, notablywater volumeandflow,aremetric(centimetersandmeters).Withintheaquacultureindustry,metricisstandard.

Wehavetriedtosimplifyandclarifythiscontradictionasmuchaspossible,thoughwerecognizeitcannotfullyberemediedastheconstructionindustrystilloperatesinimperialandtheaquacultureindustryinmetric.

ANoteonCurrencyAll salepricesandcostestimates throughout thebookaregiven inUSdollarsunless otherwise specified. Some large figure amounts are marked US$ foremphasis.CanadiancurrencyismarkedasC$.Figuresgivenare to thebestofourknowledgeasofthedateofpublication.

ANoteonNorthReferencestocompassdirectionsassumeyourgreenhouseissituatedwithnorthas indicated in Diagrams DWC OVERVIEW and TOWER OVERVIEW on

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pages 30 and 31, which allows us to easily reference locations within thegreenhouse.Forexample,thismeansyoursumpwillbeonthesouthsideofthegreenhouse. Your Seedling Table will be in the northwest corner. If yourgreenhouseissituateddifferently,adjustaccordingtoyoursite.

PropertyConsiderationsThere are several qualities to consider in situating your greenhouse.Themainconsiderationsare:

ZoningSunexposureCharacteristicsofthelandAccesstopowerandwaterPrevailingwindsWastedisposalLong-termlandrightsLivingonsite

ZoningNotall locationswillbe legallyzoned toallowaquacultureand/oragriculture.Before anyother consideration, confirmwithyourmunicipality andgoverningfisheriesbodythatthepropertyisacceptableforaquaponics.

SunExposureThe rule here is: the more sun the better. Sunlight is the primary source ofenergy for your plants, and there is no such thing as too much. It is alwayspossibletoshieldoutthesun(seeShadeClothinChapter5),butthelocationofyourgreenhouseusuallysetsafirmupperlimitonsunhoursandintensity.Payspecialattentiontohowearlyandlateinthedaythesunhitsthepotentialsite.Doyoulose thesunearly in theeveningbecause itgoesbehindaneighboringmountain,ordoesthesunhitthesitelaterinthemorningbecauseofagroveoftreestotheeast?Ifpossible,locateyourgreenhousewheretheearliestandlatestsunofthedaywillreachyourplants.Werecommenddoingasuncharttogauge

this.Chart for thewinter solstice as thiswill tell you the least sun during theyear. The duration of sun hours over thewinterwill determine the amount ofsupplementarylightrequiredforyear-roundproduction.

Asaguide,lettucerequiresaminimumof14hoursofstronglightperdaytoproduce finished heads in five weeks in a trough or tower (sprouting andseedlingstagesareadditional).Plantswillcontinuetogrowwithlesssunhoursand/or less direct sun exposure, but the production time can greatly increase,whichmeansnotonlylessplantstosellbutalsoincreasedpotentialfordiseaseandpestdamage.

Inalmosteverysituation,thegreenhouseshouldbeorientedeast-west.Inthecaseofadriptowersystem,thisismandatoryforeffectivelightpenetration.Ifthe topography of the land or extreme prevailing winds prevent you fromorienting your greenhouse east-west, a DWC system can be oriented in anydirectionwithonlyminimallossoflightpenetration.

CharacteristicsoftheLandTheprimarycharacteristicstoconsideraregradeandconstituency.Thegradeofthelandissimplytheslope,orangle,oftheland.Yourgreenhousewillneedtobetotallyflatsothatwatermovesinthedirectionyouwantitto.Asitethatisnearlyflatwillsavealotoftimeandmoneyingradingthelandtolevel.

Theconstituencyofthelandistheearthitself,typicallysand,clayorloam(amixtureofsandandclay).Whileasandysitewillbe theeasiest toworkwith,themostimportantfactoriscompaction.Theearthwillbesupportingtheweightofmanytonsofwater,particularlyunder the tanksandtroughs,so landthat isnotfullycompactedwilltendtosettleundertheweightandcauseproblemsovertime.

AccesstoPowerandWaterAquaponics relies on electrical power. It is not optional. In this book we areassuming you will be using power from the grid. Accordingly, an earlyassessment by an electrician of the costs of bringing dedicated power to thegreenhouse is vital. If you are powering your greenhouse via off-grid meanslocatedonsite,allthesameneedsapplyexceptforthegridtie-in.Evenifusingoff-grid power, we strongly suggest being connected to the grid as power

outagescanbefataltoanaquaponicfarm.Accesstosuitablewaterisalsocrucial.Wesuggesttestingyourwatersource

whileassessingaproposedlocation.Waterforthesystemshouldbeclean,clear,freeofpathogensandbacteria,andhaveapHbetween6.5and7.5.Alwayshaveyourwatertestedforbiologicalandmineralcontent(seeChapter6).

Typical sources for water are the same as those used in households: amunicipal supply, a deep well or harvested rain. Well water that has notundergonechemicaltreatmentisideal.Municipalwatercanbeusedaslongasitisfreeofchlorineandchloramines.Mostmunicipalitiesdisinfecttheirdrinkingwaterwithchlorine,whichcanbeeasilyremovedbyvigorouslyaeratingitforafewhoursor letting it stand inanopencontainer forat least24hours, thoughthisextrapurificationprocessisinconvenient.

It is important tonote that chloramines cannotbe removed from thewaterusing the aeration or 24-hourmethod.Chloramines are removed byUV light,whichispartofoursystemtocleanandsterilizethewater.Oursystemdesignwill actively remove chlorine and chloramines by design, but we recommendthat if you are usingmunicipalwater, you install an additional smallUVpre-filteronthemainwaterlinetothegreenhouse.

Westronglysuggestnotusingsurfacewater fromanaturalbodysuchasariver, lakeorpond.Doing somaybring inanynumberofmicrobialproblemsand may not be allowed by your local government without a water license.Sourcewaterissoimportantthatwesuggestseekingadifferentsiteifyouronlyoptionistousesurfacewater.Ifyoumustusesurfacewater,itmustbesterilizedandfilteredtopotablequalitypriortoentryintothesystem.

PrevailingWindsThinkofyourgreenhouseasaverylargekite.Giventherightwindpoweranddirection,hugeforcesare trying tomake it takeflight.Thisshouldnothappenwiththeproperhardwareandinstallation,butitisagoodideatounderstandthephysics and plan accordingly. If you purchase your greenhouse new from amanufacturer,makesureitisengineeredtowithstandthewindandsnowloadstypical of your area. On a standard poly covered greenhouse, the prevailingwinds shouldhit the sidewall (oneof the long, rounded sides) rather than theendwalls(theverticalwallsattheends).

The potential conflict with this is that if you opt to use drip towers, thegreenhousemustbeorientedeast-westtoalloweffectivelightpenetration.Ifyouopt to use troughs, the greenhouse can be situated in any orientation withoutsubstantialcompromisetolightcapacity.

WasteDisposalIn the normal operation of your aquaponic system, you will be manuallycleaningfilterpadswhichhavetrappedlargequantitiesoffishfecesanddebris,andflushingout theRadialFlowSeparator (RFS)andfish tankdrains.This isthe only source of water loss from the system other than evaporation andtranspiration.Thewastewater(effluent)needstoberemoved,andinmanycases(particularly in Canada), proper effluent disposal will be a condition of youraquaculture license. How you dispose of the effluent will depend entirely onyouruniquesituation.

Thesimplestmethodistodistributetheeffluenttoaleach-fieldandallowitto percolate into the topsoil. “Ground infiltration” can be done by simplysprayingtheeffluentontoahayfieldorbyconstructingadedicatedseptic-styledisposalsystem.

Inouropinion,thisislikethrowingcashonthegroundandwaitingforittosoak in because your fish wastewater is actually a form of liquid gold.Aquaponicwastewater is full of allmanner of elements,minerals and organicsolids that can be extracted and fermented (biodigested) into an amazingfertilizer, which can either be sold for extra profit or recycled back into theaquaponicsystemtosupplementnutrients.Themineral-richwaterleftovercanbeusedtoirrigateanearbyorchardorfieldcrop.

Whateveryouchoosetodowiththeeffluent,youneedtoconsiderhowandwhereyouwillcaptureit.Thedesignpresentedinthisbookhaseffluentdrainsconnected to the fish tank standpipes, the RFS and the washdown sink (forcleaning off the filter screens). These drains carry the effluent to the WasteTanksoutsidethegreenhouse.

On our farm we were able to take advantage of the natural slope of thepropertyandlocateWasteTanks(IBCtotes)about20feetawayfromthewestendwall,justbelowthegradeofthegreenhouse.Ifyourpropertyisperfectlyflatoryouareunabletotakeadvantageofthetopography,youwillneedtoexcavate

apitsothattheWasteTanksarelowerthantheMainWastePipe(seeChapter4).

TheWasteTankscangetverysmelly,solocatethemanappropriatedistancefrom the greenhouse and any nearby living areas. Youwill also need to takesteps to secure the sump or tank with a lid to prevent any accidents such aschildren or pets falling in.Whether youuse a tank or awaste sump, youwillwant a vessel that is at least 1,000 liters, which will give you 4–5 days ofcollectionbeforeitneedstobeemptied.SeeEffluentlaterthischapter.

Long-termLandRightsMostfarmersrightlyviewfarmingasalong-termproject.Developingtheland,oftenrequiringrestorationfromnon-useorpooruse,buildinginfrastructureandlearning the microclimate and what grows best can take many years andconsiderable investment of time and labor. Securing long-term land rights,whether through ownership or lease, is highly desirable. With an aquaponicfarm, it ismandatory. The infrastructure you build is the farm and should beconsidered permanent.Moving a commercial aquaponic farm is possible withlarge expense and effort, but we suggest you only consider becoming anaquaponicfarmerifyoucansecurelandrightsforaminimumof10years.

LivingOnsiteItisveryadvantageoustoliveonyourfarm.Youcaneasilycheckinonthingsinthegreenhousemultipletimesperday,youcanlikelyrespondtoemergenciesmuchmore rapidlyand it ismuchmorepleasant tohaveastrollonyour farmratherthanadriveasyourcommute.Ifpossible,planonlivingwhereyoufarmandsourceyourpropertytoaccommodatethis.

TheGreenhouseSizeJust likebuyingahome,buyingagreenhousehasahugearrayofoptionsandprices.Themostimportantthingtoconsiderissize.Thesizeofyourgreenhouseis the starting point of the entire design process. This book is based around a120′by36′greenhouse.

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Wehavedesignedoursystemarounda120′greenhouseforseveralreasons:

The greenhouse houses all necessary components under one structurewithnowastedspace.ThesystemiswithintheoptimumrangeoftheGoldenRatio(seeChapter3).If you increase or decrease the trough length bymore than about 20′, youwillbeoutsidetheGoldenRatioandwillrequiredifferentlysizedfishtanksandcomponentsthroughoutthesystem.This size of operation is ideal for a family farm: it can be farmed by 1–3people working a combined 40 hours per week and produce an excellentincome.Notethatthisestimateofhourswilldependgreatlyontheefficiencyof the farmer(s) and is an estimate of farming time only. Administration,marketingandsalesareadditional.

The work area has been designed to fit all the necessary components asefficiently as possible while maintaining a comfortable working space for alltasks.Ifyouprefertohavemoreroom,youcanbuildalongergreenhouseandexpandtheworkandseedlingareas.

If you have the option to acquire a 40′-wide greenhouse without greatadditional expense, we recommend doing so. The wider walkways betweentroughs(ortowers)andslightlymoreopenspaceintheworkareaareworthit.

It iscertainlypossible touseagreenhouseofdifferentdimensions,suchassquare, or greenhouses longer than 120′, but you will need to rearrange thelayout of both hydroponic and aquaculture subsystems to make sure they fitwithinthesize.UsetheformulasinChapter3toensurethatyourdesigniswellbalanced.

At Raincoast, we operate out of an 80′×36′ greenhouse due to sitelimitations.Ourgreenhouseisveryproductive,butwewouldcertainlyexpandto120′ifwehadroomtodoso.

IMPORTANT

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Rememberthatwheneverwetalkaboutagreenhouseinthisbook,includingestimatedprices,wearereferringtoa120′longstructurethatis36′wide,theminimumsizewerecommend.

NewvsUsedYoucanbesuccessfulwithaneworusedgreenhouse. In theend thedecisionwill likely comedown to howmuchyou arewilling to payversus howmuchwork you are willing to do to rebuild and perhaps fix a used structure.Availabilityandconditionarealsokeyfactorsifbuyingused.

The biggest advantage of a used greenhouse is price. A new double-layerpoly covered greenhouse, which is the most common type, will likely costaroundUS$25,0000forthestructureitself(notincludinginstallation,heatingorventilation). A new twin-wall polycarbonate-covered greenhouse will costaround three times that much. A used greenhouse can often be found forUS$10,000orless,thoughyoumayhavetodeconstructitfromitsprevioussite,whichisnosmalljob.

Potentialdownsidesofausedgreenhouseare:

Uncertaintyastothequalityofthestructureitself.Uncertaintyastothesnowandwindratingofthestructure.Uncertainty as to whether all components of the structure arewith it. Forexample, wind bracing may be missing and you won’t know. Missingcomponentscangreatlyreducestructuralintegrity.Ifthestructurewasmountedinconcrete,whichwerecommend(seeChapter4), it may be problematic to remount at your location (note whether thearchesareboltedontoground-stakesorsetdirectlyintotheconcrete).Limitedcapacitytochoosefeaturessuchasroll-upsides.Polycoveringwillmostlikelyneedtobereplacedimmediately.

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Anewgreenhousewillgiveyouastructurethatisdesignedforyourneeds,engineeredforyourlocationandshouldbewarrantied.Itwillundoubtedlycostmore.

TypesofCoveringThere are three main options for greenhouse covering: polyethylene (“poly”),polycarbonate and glass.Of the three, poly and polycarbonate are the twowestronglysuggestyouconsider.

Glass is by far the most expensive option. Even though glass boasts thehighest insulationvalue, it is extremely expensive to construct and repair, andforthisreasonalone,wedonotrecommendit.

Single-layer poly consists of a single layer of thin, flexible polyethyleneplastic.Polyethyleneisthesamematerialastheubiquitousplasticshoppingbag,onlymuch thicker. It has excellent light transmission and is highly diffusive,whichisgreatforgreenhousegrowing.Thisisthecheapesttypeofgreenhousecoveringandhasthelowestinsulationvalue.Wedonotrecommendsingle-layerpoly.

Twolayersofpoly,however,canbeusedtocreateabubbleofair,whichisanexcellentinsulator.Thisiscalleddouble-layerpolyandconsistsoftwolayersthat are sealed at the ends and inflated with a small fan. This is the leastexpensiveoptionthatwerecommend.

Thedownsidestodouble-layerpolyare:

Thewallscanbeeasilypunctured,thoughtheyareeasytopatch.Theaveragelifespanofpolyinfullsunisaround4–5years,afterwhichbothlayersmustbereplaced.Lowerinsulationvaluethanpolycarbonate.

Polycarbonateisamuchhardermaterial thanpolyethylene.Forgreenhousecoverings, it is made into corrugated panels similar in structure to cardboard.Thecorrugatedstructurenotonlygivesitstrengthbutprovidesmanypocketsofair ina singlepanel,whichcreatesahigher insulationvalue thandouble-layerpoly.

Polycarbonatepanelsareavailableinavarietyofthicknesses,from6mmto16mm,andas twin-wallor triple-wall (two layersor three layers).The thicker

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the material and the more walls it has, the higher its insulation value. For apolycarbonatecovering,werecommendaminimum8mmtwin-wall.

Advantagestopolycarbonatewalls:

Superiorinsulationifusingthickerthan8mmVerydifficulttopunctureLonglifespan(estimated25years)Looksfantastic

The only substantial downside, and it is significant, is that a newpolycarbonategreenhousewillcostaboutthreetimesasmuchasadouble-layerpolygreenhouse.

Afinaloptionistousedouble-layerpolyfortheroofandpolycarbonateforthe endwalls. The endwalls contain a lot of the ins and outs of the structure,including cables, pipes and ducts, and it is very easy and neat to run themthroughpolycarbonate (simply cut or drill a hole) andvery challenging to runthem through poly. This option allows you to keep costs lower while havingexcellentfunction,anditlooksgreat.

RecommendedFeaturesWestronglyrecommendyouselectallofthesegreenhousefeatures:

Largedoorsonthewestendwall.Thecapacitytoeasilybringinatractororotherlargemachineryorequipmentshouldbeconsideredmandatoryifatallpossible.Wesuggestslidingdoorsthatareatleast8′wide.Roll-upsides. Ifyouare selectingapolygreenhouse, this feature ishighlyrecommended. The sides will roll up several feet via a simple crank andallow you the highest level of ongoing control over the ventilation of thespacewithnopowerusage.Ridgeventsareanotheroptionandwillventheatmorequicklybuttendtobeexpensiveandeasilydamaged.Automatic peak vents. This powered ventilation should be used inconjunctionwiththeroll-upsides.Ittypicallyconsistsofmechanicallouversin one endwall and a large blower in the other that are controlled by athermostat.Theyarestandardinmostgreenhouses.Vented propane or natural gas heater. This is necessary in temperate or

•colderclimatesunlessyouutilizeanotherheatingmethod.Circulating fans. These are typically attached to the cross braces of thearches(thehorizontalbeamsthatlooklikerafters)andareusedinthewinterinconjunctionwiththeheatertoensurethatwarmairiscirculatedwithinthegreenhouse.

HeatingtheAirIn the winter when temperatures drop below the ideal average, supplementalheatingisrequiredtomaintainaminimumairtemperatureofatleast5°C(41°F).

Airheatingisbestaccomplishedwithanaturalgasorpropaneheater.Yourgreenhousemanufacturerwillbeabletopresentyouwiththecorrectoptionthatissizedforyourgreenhouseandclimate.Theheater,whichisusuallyhungfromthecrossbraces,issettokeeptheairataminimumtemperatureof5–7°C(41–45°F).Circulationfans,alsohungfromthecrossbraces,arespacedaroundthegreenhouseinordertorotateandmixair,ensuringairtemperatureisconsistent.

Propane use will vary greatly fromwinter to winter.Most years our totalannual propane bill is around $600, whereas in 2016/17, when drafting thisbook,weusedmorethandoublethisduetoaseverecoldsnap(andthewinterisn’tover).Propanewillalsovaryinpriceovertime.

Ventedpropanegreenhouseheater.

CoolingtheAirIn summer, or whenever the air temperature is consistently above 25°C

(77°F), it is necessary to remove excess heat from the greenhouse. Thecirculation fansare turnedoff,and theair isallowed tonaturallystratify,withhotter air rising to the roof peak and away from the crops and the cooler airsinkingtothefloor.Optionsforcoolingtheairinyourgreenhouseincludedirectmethods, such as electrically driven swamp coolers or high-pressure watermisters; and passive methods, such as ventilation and shade cloth. Ourpreferenceisforpassivecoolingmethods,astheydonotuseanyelectricity,incombinationwithactiveventilationviapeakventsintheendwalls.

Theprimarymethodofpassivecoolingistophysicallyopenthegreenhousetoallowwindtopassthrough.Thisis typicallydoneviaeitherroll-upsidesorridgevents.Ridgeventsarepanelslocatedattheridgeoftheroof,runningthelengthofthegreenhouse.Whenopened,theyallowthehotairtoescapedirectlyfromwhere it is accumulating—at the topof the greenhouse.Althoughveryeffective, ridge vents can be easily damaged by wind and snow, and can beexpensivetorepair.

Roll-up sides are common on poly greenhouses and work just like theysound:a tubewithacrankononeend isused to rollup thedouble-layerpolyfromthebaseboardtoaboutsixfeethigh.Thismethodisslightlylesseffectiveatventingtheheatthanridgevents,astheyventthebottominsteadofthetopofthegreenhouse,but theyaremoreeffectiveatventinghumidity,whichcanbeveryusefulinthewintertorapidlyremoveexcesshumidity.

Theotherpassivecoolingtoolwerecommendisshadecloth,whichisusedtocutdownonsolarradiation(directsunexposure)andthusheat(seeChapter5).

Thelastmethodofcoolingwerecommendispoweredventilation,whichissimply using a fan to actively push hot air out of the greenhouse. Vents areinstalled in the peaks of the endwalls and are controlled by a thermostat.Oneendwallwillhaveoneormore large fans toblowhot airout and theoppositeendwallwillhaveanelectricallycontrolledventthatopensatthesametimetoallowairintothegreenhouse.

Roll-upsidewithcrank.

HeatingandCoolingtheWaterHeatingair takesconsiderablymoreenergy thanheatingorcoolingwater.Wethereforerecommendyoursystemcontaintwoseparateheatingunits:oneforairasdescribedaboveandoneforwater.

Watertemperatureisoneofthemostcriticalfactorsforthewell-beingofanaquaponic system. We cannot stress this point enough. Water temperatureregulatesthemetabolicrate,andthereforethegrowth,ofthefishinthesystem;it dictates the fecundity of the beneficial bacteria; it determines the oxygencarryingcapacityofthewater;anditplaysaroleinthetranspirationprocessoftheplants.Forthesereasons,itisveryimportanttokeepthewatertemperatureinthecorrectrangeandasstableaspossible.

Peakventanddouble-layerpolyinflationblower.

One of the advantages ofDWCaquaponic systems is the thermal stabilityaffordedbythelargevolumesofwaterpresentinthesystem.Inadditiontothethermalmassofwater,extra insulationisprovidedbythefloatingraftsandbytheearththatthetanks,troughsandsumparerestingon.Additionalstabilitycanbeaddedbywrappingthefishtanksininsulation.

Insulatedfishtanks.

Despite its thermal, stability, the water temperature will be affected byfluctuatingairtemperatures,andregularadjustment,upordown,willbeneeded.HereintheCowichanValleyinBC,averagesummertemperaturescanbe30°C(86°F) forweeksonend,andwinterscan fallbelowfreezing.Sincewebeganrecordingdailytemperatures,wehaveseenthethermometergetashighas36°C(86°F)andaslowas−15°C(5°F)forshortperiodsoftime.Thegoalistokeeptheair temperaturehigher than5°C(41°F)andideally lower than25°C(77°F)andthewatertemperatureataconsistent15–17°C(59–63°F).

The system for water temperature regulation must be automated for bothheatingandcooling.

Initially we did not include a water heating/cooling system in our design.Theresultswereunhappyfishandweakplants.Webeganexploringthevariousoptionsavailablewithaneyetousingaslittleelectricityorfuelaspossible.

WehadanEnergyAssessmentdonebytheProvinceofBC,whichevaluatedtheprimaryoptions:groundsourceheatpump,airsourceheatpump,gasboilerand refrigeration system, and solar panels and refrigeration. Solar panelsweredeemedtobethemostefficient,astheyproducemuchoftheenergyonsitebutwereruledoutduetothehighinitialcapitalcost.Anairsourceheatpumphad

the second-lowest annual operational costs andwas nearly the least expensivecapitalcosttoinstall,soweoptedtouseanairsourceheatpumpunitdesignedforaswimmingpool.Theunitsitsjustoutsidethegreenhouseandhaskeptourwater at the ideal temperature since installation.We recommend using such aunit.

HeatPumpThe heat pump should be an air-to-water heat exchanger designed foraquacultureoralargeswimmingpool,capableofheatingandcoolingwaterasneeded. Correct sizing is very complex and must be done by an HVACprofessional. Your unit must be able to keep system water at 15–17°C (59–63°F)atalltimesthroughouttheyearandhaveadefrostcyclethatenablesittooperateatsub-zerotemperatures.Theinternalheatexchangercannotbecopperasthisisnotfishsafe;itmustbetitanium.

Our heat pump is an Orion series reversible pool heater made by HVACConcepts,whichhas65,000BTUsofheatingcapacity,38,000BTUsofcoolingcapacity and draws 3,500watts of powerwhen running.These figures are forreferenceonly.Ourunitissizedforourwatervolume(whichislessvolumethanthe design in this book), our local climate conditions and the thermalgains/lossesofourgreenhouse.

Ourheatpump.

TheRaincoastAquaponicsGreenhouseOur greenhouse is an 80′×36′ structurewith a double-layer poly covering andtwin-wallpolycarbonateendwalls.Ithasallofourrecommendedfeatures:largedoors on the west endwall, roll-up sides, automatic peak ventilation andcirculating fans. We use a propane heater for air heating and a heat pumpdesignedforaswimmingpooltobothheatandcoolthewater.Thegreenhousewas engineered for our specific location for both snow load and wind. Wepurchaseditnew.

WerecommendthebookTheYear-RoundSolarGreenhousebySchillerandPlinke(NewSocietyPublishers,2016).It isnotspecific toaquaponicsbut isausefulguideforallthingsgreenhouse.

GreenhouseLayoutThebestwaytothinkaboutanaquaponicsetupis tofollowthewaterfromitslowestpointtoitshighestandbacktothelowest.

The lowest point in an aquaponic system is the sump, which is fullyunderground.The sumpacts as reservoir andamixingandwater conditioningvessel.TemperatureandpHarealsocontrolledinthesump.Fromthesump,thewaterispumpedthroughUVsterilizerstothehighestpointsinthesystem:thefishtanks.Fromthefishtanks,thewaterflowsbygravitythroughtherestofthesystemandbackintothesump.ThewaterfromthetanksexitsthroughtheTankManifold,thenmovesthroughthefiltrationsystems(theRadialFlowSeparatorandCombinationFilterBox)beforeflowingthroughthetroughsandbacktothesump.

GreenhouselayoutfortheRaincoastDWCdesign.

GreenhouselayoutfortheRaincoastdesignusingZipGrow™Towers.

In theRCAdesign, each trough has two sides. Thewater flows down thenorth side of each trough,moves to the other side via a U-shaped pipe at itseasternend,thenflowsbackdownthesouthside.Astandpipeatthewesternendof the south sideof each trough controls thewater level in the trough.As thewateroverflowsintothestandpipe,itiscarriedbacktothesump.

Inatowersystem,thesumpisalsothelowestpointthatactsasamixingandconditioningvessel,butinsteadofpumpingthewaterinonelinearloopasinaDWC system,most tower designs use a split system.A split systemuses twoparallelloops,bothoriginatinginandreturningtothesump,drivenbyseparatepumps.ThefirstlooppumpswaterfromthesumpthroughtheUVsterilizerstothefishtanks,andfromthereitflowsviagravitythroughtheTankManifoldandfiltrationsystemsbacktothesump.

Thesecondlooppumpswaterfromthesumpanddistributesittothetopofthe towers,which are arranged intomultiple zones, or arrays.Thewater dripsthrough the towers and collects in gutters under the towers. The water flowsdown the gutters and returns back to the sump. In a tower system, it isparticularly important that the sump is designed for propermixing of the twoloops.

TroughsTroughDesignPrinciplesSpace in agreenhouse is finite, andmaximizing its usewill directly equate toincreased profits. We have designed our layout to maximize the usableproductionareaandtoallowforeaseofworkineacharea.

Aprimaryconsiderationfortroughsisthecommonlyavailabledimensionofstyrofoamthatwilldictatethesizeoftheraftsandthusthewidthofthetroughsandtroughlayout.Thetroughlayoutiswhatdeterminesthatthegreenhousebeatleast36′wide.

The common dimension of styrofoam, including what we use andrecommend, is 8′ long × 2′ wide. This is far too big to comfortably handle,especiallywhenfullyloadedwithlettuceandwetroots.Aloadedraftofthissize

couldeasilyweigh70–80lbsandwouldbreakifyoutriedtoliftit.The solution is to cut the sheets in half into 4′ lengths that can be easily

managed. This 4′ length dictates thewidth of one side of a trough and is thedimensional startingpoint fromwhich tobegindesigning theoverall layoutofthegreenhouse.

Inthe120′greenhousedesignpresentedinthisbook,86′isdedicatedtothetroughs.Eachsideofatroughwillhold43rafts.Ifyouoptforadifferentlysizedgreenhouse or rafts, remember that the raft dimension dictates the insidedimensionofthetrough.Youmustalsoallocateenoughspaceforthethicknessofthethreewallsofthetroughframesplusaninchorsoextrapersidetoallowforraftstobeeasilyinserted,movedandremoved.

Thesecondmajorconsiderationisthelayoutandspacingoftheholesintherafts,whichdetermineshowmanyplantscanbegrownandwilldirectlyimpactplanthealthandgrowth.Ifplantsaretoofarapart,youwillbewastinggrowingspaceandreducingyields.Plantstooclosetogetherwillleadtostretching,poorgrowthandincreaseddiseaseandpests.

Tocomplicate things further, consider thatplantswillbequite smallwhenenteringtheraftsandquitelargewhenharvested.Insertingyoungplantsintotherafts with the more widely spaced layout required for mature plants will notmaximizeavailablegrowingspace.Alternately,insertingplantsinatightpatternbutnotthinningorspacingthemastheymaturewillleadtocrowding.Neitheroftheseissatisfactory.

Meeting the demands of growing plants by using rafts with different holelayouts requires buying lots of expensive styrofoam and storing it when notbeing used.Our solution is to use rafts that have a hole layout thatmeets theneedsofbothyoungandmatureplants.

Each4′×2′ rafthas32sites,evenlyspaced inrows4wideby8 long.Eachsiteis6″oncenterfromitsfouradjoiningneighborsandwillallowyoutouseoneraftdesignforallstagesofplantgrowth.Immatureplantsareinsertedintotheraftsusingall32sites.Whentheplantsstarttouchingeachother(abouttwoweeks in), they are double-spaced in a diagonal pattern until harvest. SeeChapter9.

TheRCATroughs

The tanks and work area will require 30′ of greenhouse length. For ourrecommendedgreenhouse lengthof120′, theplantproductionareawill be86′withtheremaining4′asawalkwayattheeastend.

One of the unique qualities of the RCA design is the two-sided trough,developedtomaximizetheavailablegrowingarea.Byusingback-to-backsidesrather than the commonly employedmethod of a 4′ troughwithwalkways oneachside,onemore4′-widetrough(onesideofatroughinourdesign)canbefitinthewidthofa36′-widegreenhouse.Thisisanincreaseof20%intotalplantgrowingarea.Inadditiontotheextraproductioncapacity,thisdesignischeaperto build as there is lesswood required to build the trough frames and far lesspipe required. The only downside is that the side of a raft farthest from thewalkwaycanbedifficulttoreachforshorterpeople.Thiscanbeovercomewithalittlebitof“greenhouseyoga”orbysimplyliftingoneendoftheraftoutandpullingitclosertothewalkway.

The total width of each trough is 8′9″: 8′ for the rafts, 3″ for the gapsbetweentheraftsandframes(1.5″perside),and6″forthethicknessofthethreetroughwalls. In a 36′-wide greenhouse, thiswill leave 29″-widewalkways.A40′-widegreenhousewillhave41″walkways.

The trough frames are constructedof lumber andplywood linedwithLowDensityPolyethylene(LDPE).TheLDPEmustbeatleast20mil,andnomorethan 40 mil. Note that “mil” stands for thousandths of an inch, not formillimeters.Westronglyrecommendusing20mil,asitisthickenoughforthejobandmuchmorepliablethan40mil.TheLDPEmustbewhiteonatleastoneside (the side that you can seewhen installed). The color on the other side isirrelevant.YoumustuseLDPEasitisafood-gradecontactsurfaceandtotallynon-toxictoallorganisms.Vinylliner,althoughcheaper,hasatendencytoleachplastic softeners into water over time, and many vinyl pool liners have anti-microbialchemicalsmanufacturedintotheplastictocontrolalgaeandbacterialgrowth.Thesechemicalsarehelpfultokeepingapoolcleanbutverydetrimentaltoanaquaponicecosystem.TherearealsoEPDMlinersdesignedforpondsthatareadvertisedas“fishsafe”butarenotafood-gradecontactsurface.UseonlyLDPE.

Yourtroughswillbe13″tall.Thewaterinthetroughswillbeapproximately10″deep.

It is important that thesurfaceonwhichthetroughsarerestingisperfectlyflat andwell compacted. After the trough frames have been assembled, a 1″-thick bed ofmasonry sand or other clean, rock-free sand is spread inside theframesandtampedflat.Thisistoensurethatthelinerwillnotbepuncturedbyany sharp edges, which is surprisingly easy when there are around 60 lbs ofpressurepersquarefootpushingdownontheliner.

RaftsRaftsaremadeofaspecifictypeofstyrofoam:extrudedpolystyrene.Thisistheonly type of styrofoam that is suitable for aDWC system, as it is chemicallyinertandwillnotleachanythingtoxicintothewater.Youmustavoidallothertypes of styrofoam, notably anythingwith polyisocyanate, which is extremelytoxic, or anythingwith a fungicidal or anti-microbial coating. If youhave anyuncertaintyaboutthestyrofoam,refertotheMSDSoftheproduct.

Styrofoamtypicallycomesin2″-thicksheetsof8′×2′,whichyouwillcutinhalftomake4′×2′rafts.Use“squareedge”styrofoam.Avoidlap,pre-scoredortongue-and-groovestyrofoam.Raftsthinnerthan2″shouldnotbeused.

Eachraftwillhaveapatternofholescutoutofit,andbepaintedwith100%acryliclatexpaintononesideforincreasedUVprotection.2″netpotsareseatedintheholesandhousetheplants.Rootsdanglethroughthestyrofoamholesintothenutrient-richwater.

FishTanksThebasicrequirementsforafishtankareverysimple:aroundwatertighttankthathasonelargeoutletatthebottomforwatertoexit.Waterisinputeitheroverthelipofthetankorviaabuilt-ininletnearthetopofthetank.

Insmallaquaponicsystems,avarietyofreservoirscanserveasafishtank.Forbackyard systems, a simple50–60gallonbarrel canworkwell.For largerhome systems or very small commercial systems, adequate tanks can beconstructedfromcisternsorcanbemadeyourself.

Forlargercommercialsystemslikethatdescribedinthisbook,wherehavingproperlargeplumbingconnectionsisrequiredandwhereaproblemwithatanksuchasasuddenleakcanleadtolossesoflargecohortsoffish,fiberglasstanksbuilt specifically for aquaculture are the only sensible option. New fiberglass

tanks for our design should cost less than $10,000 total and are worth everypenny.We recommendagainst any typeof home-made tank for a commercialfarm.

Raftshownwith32-holespacing.

Aquaculture tanks are specifically designed and built to raise fish. Mostimportantly, they shouldnever leakas longas theyareproperlyplumbed,andtheyhave a lifespanof about40years.Theyhave abuilt-in largedrain at thebottomthatisessentialforourdesign.

Good-quality fiberglass tanks are built to last, so youmay be able to buythem secondhand. If possible, have secondhand tanks inspected by someoneexperiencedpriortobuying.Inmostcases,westronglysuggestpurchasingnew

fiberglass tanks from a reputable aquaculture manufacturer. Our tanks weremanufacturedbyPRAquaandcanbepurchasedthroughPentair.

We use a four-tank system,meaning youwill have four fish tanks. Threetanks are 8′ diameter by 3′ deep and are used to raise the cohorts. These arelabelledTanks1,2&3.Thefourthtankis4′by3′andisusedtopurgethefishpriortoharvesting.ThisisthePurgeTank.

Thetanksarelaidoutinaspecificpatternforoptimumspaceusage,easeofwork and easeofplumbing.The layout and installation is covered indetail inChapter4.RaisingfishiscoveredinChapter8.

EachofthefourtankshasanexternalStandpipeAssembly(SPA).EachSPAis connecteddirectly to thebottomdrainof a tank, controls thewater level inthattankandactsasaraiseddrainbylettingwaterexitthetankhigherthanthefiltration components.TheSPAalso allows the tank tobedrained, as needed,into theWasteTanks.Construction and installation of theSPAs is covered inChapter4.

The final component in the tank system is the TankManifold. The TankManifold sits betweenTanks1, 2&3 and serves to combine the outletwaterfrom the three tanks before it flowsdownstream to the filtration systems.TheTankManifoldismadefroma50–60gal.food-gradeplasticbarrel.

Thefishtanks,TankManifoldandfiltrationsystems(RFSandCFB)atourfarm.

FiltrationSystemsFiltrationinanaquaponicsystemcanbedividedintotwocategories:mechanicalfiltrationwhich removes solidwaste and biological filtrationwhich detoxifiesammoniaandmineralizesparticulates.

Filtrationisoneofthemostcriticalcomponentsofanaquaponicsystem.Itisoften either under-or over-designed in its ability to effectively remove solids,process fish waste and control pathogens. There are numerous types andmethodsoffiltrationavailablefrommanydifferentmanufacturers,andthereareanequalnumberofopinionsonthebestcomponentsandmethods.Thefiltrationsystemsweusearebasedprimarilyoncommercialaquaculturestandardsandareproventoworkinourdesign.

Theprimarydesignconsiderationswhenchoosingafiltrationsystemare:

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•

•

•

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Solidsremovalcapacity.Fishproduceasurprisingamountofwasteeveryday. It isessential to removeall,oralmostall,of the largeparticles,whileallowingsomeofthefinesuspendedparticlestoremaininthesystemtobemineralized. Finer screens ormeshwill capturemore particles and requiremorefrequentcleaningthancoarsescreens.Water flow.Water flow through the filtration components is powered bygravity. Accordingly, the filters must be able to capture solids withoutimpeding or restricting the water flow as this could cause upstreamcomponentstooverflow.Finerscreensormeshimpedewaterflowmorethancoarseones.Costtobuildorpurchase.Thisisself-explanatory:lessexpensiveisbetter,aslongaseffectivefiltrationisnotcompromised.Energy consumption. Powered filtration systems consume energy andincrease your operating expenses. Minimizing power consumption savesmoneyandmakesyoursystemmoresustainable.Easeandfrequencyofcleaning.Agoodfiltrationsystemshouldbeeasytoclean and maintain. A poorly designed or undersized filter requires morefrequent cleaning to ensure correct operation, which increases labor andwater use. The difference between a system that requires cleaning everythreedaysversusonceoreventwicedailycannotbeoverstated.

MechanicalFiltrationMechanical filters will remove the largest unwanted items from your waterincluding fish feces, excess fish feed, clumps of algae and other debris. Themechanical filtersmustbecapableof trapping largeamountsof solidswithoutimpedingorrestrictingflowofwater,ideallywithoutusinganyelectricity.

Thereareafewdifferenttypesoffiltersthatfittheserequirements,eachwithbenefits and drawbacks. Some types of solids filters, such as rotary drumscreens, require energy to operate and use large quantities of fresh water forbackwashing.Othertypes,suchascartridgeorbagfilters,havenomovingpartsanddon’t requireanyenergy tooperate,but thewatermustbe forced throughthemunderhighpressure,whichrequiresextrapumpsandthusmoreelectricity.Neitheroftheseisidealforanaquaponicsystem.

SwirlfiltersandRadialFlowSeparatorshavenomovingparts,consumeno

electricalenergyandallowaveryhighflowrate.RadialFlowSeparatorsareamoremoderndesignandaremoreeffective.OursystemusesanRFS.

ThedownsidetoanRFSis thatwhileit isveryeffectiveatcapturinglargesettleablesolids, itdoesnotcapturesmallersuspendedparticles.RFSsarealsofairly expensive, although worth every penny in our opinion. Homemadeversionstendtonotperformnearlyaswellascommercialaquacultureversions.Youcanexpecttopayabout$3,000foranew36″RFS.

Screenfilterscomeinallshapesandsizesandcanbeeasilymadefororbyyou.InChapter4weprovideyouwithourcustomdesign,sizedspecificallyforoursystem.

Screens come in a wide variety of materials, and there are manymanufactured options. By using the right filter body dimensions and screentypes,thesekindsoffiltersprovideexcellentsolidsremovalcapacity,goodflowrates,lowcleaningfrequencyandhigheaseofcleaning.

BiologicalFiltrationBiological filtration is the decomposition of organic materials bymicroorganisms. Inanaquaponicsystem, thisoccurs in twodistinctprocesses:nitrificationandmineralization.WediscusstheseinChapter6.

Biofilters,likemechanicalfilters,canbeboughtormadeandareavailableinawidevarietyoftypesandsizes,fromfluidizedsand-bedfiltersandpropeller-washed bead filters to trickling sponge filters andMoving Bed Bio-Reactors.Regardlessofthetypeofbiofilter,theprincipleisalwaysthesame:someformofmediawithahigh surfacearea is contained inavessel andwater ispassedthroughthemediasothatthebacterialcoloniesonitssurfacescomeintocontactwiththeammoniainthewater,allowingthebacteriatooxidizetheammonia.

In DWC aquaponic systems, biological filtration occurs on the walls andfloorsofthetroughs,theundersideoftheraftsandanyotherdark,well-aeratedsurfaces such as the inside of pipes. Plant roots also contribute to biologicalsurfaceareaandcanroughlydoubletheavailableBSA.Intower-basedsystems,thetowermediaprovidesthesurfaceareafornitrifyingbacteriatogrowon.Theamount of surface area in an aquaponic system that can be colonized bynitrifyingbacteriaiscalledtheBacterialSurfaceArea(BSA).

BSAdirectlycorrelatestothepotentialquantityofbeneficialbacteriainyour

systemandthustheprocessingpowertoconvertammoniaintousefulminerals.YoucanneverhavetoomuchBSA.AsdiscussedinChapter1,DWCsystemshave a relatively low BSA, so we designed our system to include a separatebiofilterwhichiscontainedintheCombinationFilterBox(CFB).

RCAFiltrationSystemsOursystememploys fourstagesof filtration.The first filters in thesystemarethe fish tanks themselves.The circular design and the angle of thewater as itenters the tanks create a constant swirling motion which forces waste to thebottomof the tank.By lifting the StandpipeAssembly (SPA) on each tank atleast once per day, themajority of the collected effluent is removed from thesystemtotheWasteTanks.ThesecondstageisaRadialFlowSeparator(RFS)totraplargesettleablesolidsassoonastheyexitthefishtanks.Thethirdstageisasetofscreenfilterswhichtrapsuspendedsolids.ThefourthstageisaMovingBedBio-Reactor(MBBR).ThescreenfiltersandMBBRarebothcontainedintheCombinationFilterBox (CFB).TheCFBgreatly increases theBSAof thewholesystem.

RadialFlowSeparator(RFS)The RFS is a passive conical settling vessel with no moving parts that isdesigned to quickly and gently remove heavy solidwaste from the system. Itworksinthesamewayasaswirlfilterexceptthatinsteadofmovingthewateraroundahorizontalaxis,thewaterismovedaroundaverticalaxis.Swirlfilterswere industry standard for some time.We recommend an RFS as it is abouttwiceaseffectiveatcapturingsolids.

WaterenterstheRFSinthecentralstillingzoneandthenisforceddownintothesettlingchamber.As thewater flowsdownwards, itsvelocitydropsand itsdirection reverses into theouterpartof thechamber, causing solids toquicklysettle to the conical bottom. The accumulated solids are periodically flushedfrom the unit using the internal standpipe. Clean water exits the RFS by theoverflowweiratthetopoftheunit.

TopoftheRFS,showingthestillingchamberandtheoverflowweir.

RFSs are available from various aquaculture supply companieswith someminor differences between them.We recommend a 36″RFSwith a 45-degreeconefora120′greenhouseusingoursystem(notethat36″isthediameterofthesettlingcone,nottheactualdiameter).AnRFSofthissizewillbeoperatingatslightlyabove its intendedsettlingvelocitybut is recommendedforourdesignduetospacelimitations.Itwillstillbeveryeffectiveattrappinglargesolids.

CombinationFilterBox(CFB)TheCFBwasdesignedbyusandmustbecustombuiltbyorforyou.IthousesfilterscreensofvariousporositiesandaMovingBedBio-Reactor(MBBR).

TheCFBisarectangularbox2′wideby2′highby5′longandcanbemadefrom food-grade plastic, aluminum, stainless steel or fiberglassed plywood.Unlessyoucan findaprefabricatedplasticboxof theexactdimensionsorarehandywithweldingandmetalfabrication,wesuggestbuildingtheCFBoutofplywoodandfiberglassingtheinsidetowaterproofit.

TheboxhasawaterinletontheupstreamsidefacingtheRFSandawateroutletontheoppositesidewhichleadstothetroughs.Ithasaremovablelidandis fitted with a series of ribs on the inside walls that form slots for holding

filtrationscreensinplace.The filter screensaremadeof curlyplastic fiberswoven intomesh sheets.

The screens are arranged in a specificorder,with the lowestdensityupstreamfollowedbymiddensityandfinedensity.Thescreensareremovedandcleanedaboutevery3–4days.WeuseandrecommendscreensmanufacturedbyMatala.

CFBwiththelidremoved.NotethisphotoshowstheCFBonourfarm,whichisaslightlydifferentdesign.

The MBBR is a simple but effective type of biofilter. The open spacebetweenthefilterscreensisfilledwithabiologicalfiltermedia,whichprovidesalargesurfacearea(BSA)fornitrifyingbacteria.Theareaisvigorouslyagitatedusing air stones connected to the aeration system. The media we use andrecommendisSweetwaterSWXbio-media.

TheCFB is designed to exact dimensions for the design in this book. SeeChapter4forconstructiondetails.

UltravioletSterilizationUltraviolet (UV) sterilization controls algae and harmful pathogens, and weconsider it mandatory for both DWC and tower systems. The UV light

eliminates organisms by rupturing their cell walls and destroying their DNA.Movingwater throughUVunits at the required intensitywill kill virtually allharmfulandbeneficialorganisms.

Asanaquaponic systemreliesheavilyonbeneficialbacteria, it isessentialthat theUVonlybeplacedbetweenthesumpandthefish tanks.UsingUVinthis manner does not impact the beneficial bacteria cultures downstream andmaximizesfishhealthbymovingsterilizedwatertothefishtanks.

Inadditiontopathogencontrol,UVdissociatesfreechlorineandchloraminein thewater,bothofwhicharecommon inmanymunicipalwatersourcesandboth of which are toxic to fish and bacteria. UV may also degrade certainbotanical pesticides that could potentially make their way into the water.Pyrethrins, for example, is well-known to degrade quickly with exposure tosunlightandinthepresenceofwater,sotheuseofUVmayprovideasafetynetforsomepesticideresiduesinyourwater.

UV light is classified as UV-A, UV-B or UV-C, corresponding to thewavelengthinnanometers(nm)oflightradiationproduced.ThepeakgermicidalefficiencyofUV light is 264nm,which is in theUV-C range (200–280nm).YourUVunitsmustberatedforUV-Coutput.MostUV-Clightsemitat254nmwhichisveryclosetoideal.

TherearethreetypesofUVbulbsusedintreatmentsystems:high,mediumandlowpressure.Medium-and-highpressurebulbsarepolychromaticandemitUV light across a rangeofwavelengths.Thesebulbs are typicallymuchmoreexpensive,haveashorterlifespanthanlowpressurebulbsandarebettersuitedtoapplicationssuchassewagetreatmentorswimmingpools.Low-pressureUVbulbs aremonochromatic and emit onewavelength ofUV light,making themideal for microbial sterilization in aquaculture and aquaponic systems. Low-pressurebulbsarealsolessexpensive,moreefficientandgenerallyhaveamuchlongerlifespan(1–2years).

IMPORTANT

TheUVlightsmustbelow-pressureUV-Clightsat254nm.

Thefluence,orUVdose,ofanultravioletbulbismeasuredinmillijoulespersquarecentimeter (mJ/cm2).TheUVdose isdirectly impactedby thespeedofthewaterasitmovespastthebulb.Theslowerthewater,thelongeritisexposedto UV and thus a higher UV dose. The faster the water, the less time it isexposedandthusalowerUVdose.

Forexample,theunitsweuseonourfarm(SmartUVHigh-OutputE150S)putout180mJ/cm2 at65 litersperminute (LPM),butonly30mJ/cm2 at387LPM.Thewateronourfarmflowsatapproximately130LPM.WeusetwoUVunits in parallel, which means the total flow through each unit is 65 LPM.Accordingly,eachunitisputtingoutatheoreticaldoseof180mJ/cm2.

We say “theoretical,” as the mJ/cm2 rating you will see listed on all UVlightsisbasedontestingdonebythemanufacturerunderperfectconditions.Theactual transmission of UV light through water, known as UltravioletTransmittance(UVT),willalwaysbelessinanaquaponicsystemduetowaterturbidity(mainlyeffluentandalgaeinthewater)andthehighdissolvedmineralcontent.

Whilethequalityandclarityofwaterwillvaryfromfarmtofarmandfarmerto farmer, the commonly accepted average loss ofUVT in an aquaculture (oraquaponic) system is approximately 25%. This means that at our farm thetheoretical output of 180mJ/cm2 is actually closer to135mJ/cm2. In a recentUVTtestbyanindependentlab,ourwatertestedat80%UVT(20%loss).

IMPORTANT

Addinghumicacidtosystemwater,commonlydonetoshadethewaterandpreventalgaegrowth,mustnotbedoneinourdesignasthiswilldramaticallydecreaseUVT.

TheUVdoserequiredtokillanorganismwillvarywidelyfromspeciestospecies. Common algae, such asChlorella vulgaris, are controlled at 22 mJ/cm2,andthepathogenicAeromonassalmonicidaiscontrolledataverylow3.6mJ/cm2.However,Flavobacteriumpsychrophilum,whichwehavefound tobethemostUV-resistantpathogeninoursystem,isonlydestroyedatadoseof126mJ/cm2.WethereforerecommendthattheUVsterilizersbecapableofgivingaUV dose of at least 130 mJ/cm2. Factoring in UVT losses of 25%, the unitsshouldberatedataminimumof180mJ/cm2atyourflowrate.

Ifyouareusingourdesignwiththree8′diameterfishtanks,withaminimumrequiredwaterflowof270LPM,youwouldrequirefourofthesameUVunitsweusetoachieveatheoreticalUVdoseof180mJ/cm2andanactualUVdoseof approximately 130mJ/cm2. If your systemmoveswatermore rapidly, youwill require additional or larger units to maintain the required UV dose. SeePumpslaterinthischapter.

UVbulbs should be replaced every year.While theywill continue puttingoutlightlongpastthistime,theoutputisconstantlydegradingandwilldegradeto unacceptable levels that may not effectively control all pathogens. SeeChapter11forreplacementinstructions.

Initially, we did not include UV sterilization in our system, and we hadongoingdisease issueswithour fish.We lostwholecohorts.Whilewecannotstate with certainty that UV solved all disease issues, since installing UVsterilization,wehavehadonlyminimaldiseaseissuesandhavelostnocohorts.UV is not a guaranteed solution to all disease andpathogens, butwe stronglybelieveitgreatlysupportsfishhealthaslongasyourwater,asitenterstheUVunits, appears clear enough to drink. Once your system is established, we

recommend testing the UVT of your water to ensure that the correct dose isbeingachieved.

Our UV units cost approximately $1,000 each, the replacement bulbsapproximately$120,andeachunitdrawsacontinuous150wattsofpower.Wehave never regretted the expense. We consider adequate UV sterilizationmandatory.

SupplementalLightingInorder toproduceyear-roundatmost latitudeswherecold-water systemsaremoreprudent,supplementarylightwillberequiredforatleastpartoftheyear.

For optimal production, plants require a certain quantity of light per day.Light is often measured in lumens, but the superior measurement is PAR(Photosynthetically Active Radiation, which is measured in micromoles. Alumenisameasureofthetotallightvisibletothehumaneye.APARmicromoleis ameasure of the total number of light photons (particles) that is usable byplants. The problemwith using lumens is that plants view and use light verydifferentlythanhumans.

Therearesome602quadrillionphotons ineachmicromole.Amole isonemillion micromoles. Each type of plant has its own light requirements foroptimal production. In general, lettucewill require about 250micromoles persquaremeterpersecond,orabout17–25totalmolespersquaremeterperday.This is called theDailyLight Integral (DLI), ameasureof light intensityovertime.

Fullsunlightisaround2,000micromolespersquaremeterpersecond,whichmeansthat25molesisachievedinabout3.5hoursoffullsunlight.However,asconditionsarerarelyoptimumanddelicateplantssuchaslettucecannothandlefullsunlight,thismustbespreadoutthroughouttheday.Insummer,shadeclothprotects thelettucefromfullsunlight,but inwinterwhenlight levelsarepoor,supplementallightingisrequiredtoachieveaDLIof17–25molesperday.

GavitaPro1000-DEonaLightRailmover.

As a general rule, lettuce needs no less than14hours of sunlight per day.According to the Cornell University CEA Hydroponic Lettuce Handbook,commercial lettuce production requires 16–18 hours per day. At our farm insouthwest BC, we use supplementary lighting at various levels for about sixmonthsperyear—fromfallequinoxtospringequinox.Ofthisperiod,months1and6generallyarelitfortwohoursateitherdawnordusk;months2and5arelitfortwohoursatdawnanddusk;andmonths3and4(theheartofwinter)arelitfor3ormorehoursatdawnanddusk.

HID(HighIntensityDischarge)lightingmaymakeyourgreenhousevisibleformilesinthedark,andyourneighborsmaynotappreciatethislateatnightorearly in the morning. Accordingly, we suggest dividing your supplementarylightingtobeonatdawnanddusk.

Werecommendusing1,000WHIDlampson lightmovingrails.A1000Wlighthung4feetabovetheplantswillcoverthewidthofatrough(8′)andwheninstalledonalightmovercancoverabout20linearfeetofthetrough.Fora120′greenhousewith86′troughs,youwillneed4lightspertrough,or12lightstotalforthreetroughs.

WeuseandhighlyrecommendGavitaPro1000WDElightsforthetroughs.We also use and recommend LightRail light movers. See Chapter 4 forinstallationinstructions.

Youwillalsorequiresupplementallightingforthegerminationchamberandseedlingarea.

GerminationChamberOursystemisdesignedtostarteachplantfromseedinagerminationchamberbefore moving the seedlings into the greenhouse. Alternatively, you canpurchaseplantstarts.Achievingahighlevelofgerminationdependsmostlyontheenvironmentalconditions,notablytemperature,humidityandlight,aswellastheageandqualityoftheseeds.

Thisdesignincorporatesaclimate-controlledGerminationChamberattachedto thewalk-incooler that is sized toproducesufficient seedlingplants foroneweekofproduction.Forthree86′troughs,theboxshouldbecapableofholdingatleast15standardnurserytraysthatare11″×22″.

If you are building a system of a different size, you can determine theamountofseedlingsneededtogerminateeveryweekbydividingthenumberofplantsitesinthetroughsbythelengthoftheexpectedgrowthcycle.

Theformulatocalculatethespacerequirementforseedlingsis:

(A×B×C)D×1.2E=X

WhereA=numberoftroughsides

WhereB=numberofraftsperside

WhereC=numberofharvestedsitesperraft

WhereD=averagegrowthcycleofplantsintroughs

WhereE=numberofcellspernurserytray

WhereX=numberoftraysrequired

Thecalculationforourdesignis:

6(troughsides)×43(raftsperside)×24(averageharvestablesitesperraft)=6,192plantsites

Inanaveragegrowthcycleof5weeks,youcanexpect:

6,192/5=1,238plantsperweek

plus20%overagetoallowforlosses=1,486

1,486/98cellspertray=15.16

We round this down to 15 trays.TheGerminationChamber design is twolevelsandholds18traystotal.SeeChapter4forconstructiondetails.

The ideal temperature to germinate most seeds is 15–18°C (59–64°F).Heatingwillbeaccomplishedviaasmallelectricheaterorheatingmatsunderthe trays. Cooling is accomplished by stealing some of the cold air from thewalk-in cooler via a small fan through the adjoining wall. Both the fan andheaterarecontrolledbyadual-tempthermostatthatturnstheheateronwhentoocoldandthefanonwhentoowarm.Thechamber is insulated tominimize theimpactofextremeoutsidetemperatures.

Thehumidityoftheseedlingtraysmustbekeptbetween75%and85%.Thisisaccomplishedbyplacingstandardhumiditydomesovertheseedtraysforthedurationofthegerminationperiodplusafewdaysintheseedlingarea.

Seedsdonotlikeintenselight.WerecommendusingasingleT5fluorescentlampovereachtray.Lampsshouldbe6,000Korhigher.Thelampsmustbeonforatleast20hoursperdayandcanbelefton24hoursperday.Wesuggest20hoursperday.

The first leaves to appear are the cotyledon. These are the tongue-likeembryonic leaves containedwithin the seed that allowyoung plants to absorbinitialmuch-neededlight.Cotyledonlookdifferentthantrueleaves.Trueleavesgrowbetweenthecotyledonandsignal that theseedlingsarereadytomoveassoonaspossible toanareaof light intensitycloseorequal towhat thematureplantsaregrownin.

OurGerminationChamber.Notethatoursisonlyonelevel,andweusedifferentlights.

SeedlingAreaThe seedling area is the intermediary, second stage of plant growth in thesystem.Heretheyoungplants,withonlytheirfirstsetoftrueleaves,willgrowto be sturdy small plants over 3–4 weeks. During this time, the plants willestablishstrongrootsandgrowsubsequentsetsoftrueleaves.

Keepthelidsonthetraysforthefirst2–3daysaftermovingthemfromtheGerminationChamber.Forlettuce,after3–4weeksyoucanexpecttheplantstobeabout2–3″tallwith3–4setsofleaves,atwhichtimetheyarelargeenoughtotransplantintothemainsystem.

Once the domes are removed, the environmental conditions for the plantswillbethoseofthegreenhouse.Forbestresultsinthecoldseason,westronglysuggestaddingbothunderrootheatingandsupplementallighting.Theseedlingswillonlyrequirebottomheatforthefirstcoupleofweeksaftertheyaremoved

fromtheGerminationChamber.Heating mats are the simplest and most effective root heating option.

Available in a variety of sizes to fit your tables, the mats must be 100%waterproof.Werecommendheatingmats.

Seedlingswillrequiresupplementallightingforthesameperiodastheolderplantsinthetroughs.Ofallplantstages,seedlingsrequirethehighestamountofdailylight.Accordingly,whiletheolderplants inthetroughswilldofinewithlights on light movers, thus less exposure, the seedling area should beilluminatedintotalitywhenthelightsareon.Forthispurpose,wesuggestusing400WMetalHalide(MH)orenhancedHighPressureSodium(HPS)lamps.Youcanalsouse600Wlamps,whichcancoverawiderarea.

Mountfixedlampsovertheseedlingareatables.Thelampsshouldbekeptapproximately2′–3′abovetheplantsatalltimesandwillcoverupto6′oftablelengthperlamp.SeeChapter4formountingoptions.

There are a number of methods of watering seedlings including severalautomatedmethods.Werecommendsimpletopwateringbyhandusingasmallpumpandhosewithadiffusivenozzle.Thewaterfromthetroughsistheidealsource.Simplyplaceanoil-lesspumpintotheoutletendofatrough.

Theplantsrequirewateroncetotwicedaily,dependingontheirmaturityandtheairtemperature.Wateringtakesjustafewminutesandisagoodopportunityto regularlyobserve thehealthofyourplants.Remember that theyounger theplant, the more delicate it is. Regular observation and adjustments paysdividends.Removedeadorweakplantsimmediately.

We strongly recommend that yourSeedlingTablebeonlyone level ratherthan stacked. The obvious disadvantage to this is the area required. Weexperimentedwithnumerousstackeddesignsandartificial lightingoptionsandfound all unsuccessful or not nearly as successful as a single level. Problemswith multi-level tables include poor growth due to a lack of natural light,humidityissuesandincreasedpests.Havingtheseedlingsunshadedintheopengreenhouseenvironmentfaroutweighstheextraspacerequired.

The total area required for theSeedlingTable is calculatedbymultiplyingthenumberofseedlingtraysgerminatedeachweekbythenumberofweekstheywill spendon theSeedlingTable.Weknow that for a five-week cycle (in thetroughs)werequire15 trays tobegerminatedperweek.Plantswillspend3–4

weeksintheseedlingarea,thustheSeedlingTablemustbeabletoholdatleast60 trays (15 trays × 4 weeks). The layout as shown in the diagram DWCOverviewonpage30allowsfor63totaltrays.

Water:TheLifebloodoftheFarmOne of the biggest advantages of aquaponics, both for the farmer and theenvironment, is the dramatically reduced water consumption over traditionalfarming.Onatraditionalsoil-basedfarm,theaverageheadoflettuceusesupto15 liters ofwater during production.We use less than 2 liters to produce thesame lettuce.Once you are operational, you can very accurately calculate thetotalwaterperplantbymeteringthetotalwateraddedtothesystemforaweekthen dividing this amount by the number of plants harvested. Calculating thisoverlongertimeperiodswillincreasetheaccuracy.

Despitethesmallamountofwater“consumed”bythesystem,largeamountsofwaterarepresentinanaquaponicfarm.It isconstantlyswirlingthroughthefishtanksandflowingdownthetroughs(ortricklingdownthetowers).Our120′DWCsystemwillhaveapproximately66cubicmetersofwaterinitatalltimes.A120′driptowersystemwillhaveapproximately20cubicmeters.

Themajority ofwater used by the system is due to flushing the fish tankSPAsand theRFS.Flushingoccurswhenyouquickly removeand replace (or“pop”)theSPAsonthetanksandtheRFSforlessthanasecond,thusflushingcollectedlargeparticulatematterfromthesystem.Transpirationandevaporationaccountfortheadditionalwaterusage.

Monitoring and regulating water parameters is one of the most importantroles of an aquaponic farmer. Often this will simply mean ensuring that theelectronic monitors and controllers are functioning properly, but it will alsomeanconductingperiodicmanual tests thataremorefoolproof thanautomatedtools. The water quality parameters of note are: temperature, pH, ammonia,nitrites, nitrates and mineral content (notably calcium, potassium, magnesiumandiron).

WaterTemperatureAsdiscussedinChapter1,thereareseveralreasonsandadvantagestofarming

in a cold-water system.Theoptimum temperature foryour system is15–17°C(59–63°F).Youshould strive tokeepyourwaterwithin this rangeat all timesandnomorethanplusorminus2degrees.Thisshouldnotbeaproblemasthetemperaturewillbecontrolledbyaheatpump.

Between 15–17°C is the range in which the balance of the differentbiologicalneedsinyoursystemisbestaligned.Weoperateoursystemat16°C(+/-1°),whichisidealforfishandwithintheidealrangeforplantgrowth.Itis,however, very low for the bacteria, which have a 50% decrease in ammoniaoxidizingcapacitycomparedto25°C(77°F)water.Evena1–2°increaseintempabove15°willsignificantlyimprovebacterialperformance,butthiscomesattheexpense of trout health because that species is not well-adapted to warmertemps.

Aquaponicsrequireselectricitytorun,andourgoalistodesignandoperatethe system as efficiently as possible. Aside from the supplemental lights,conditioning the water is the biggest electrical consumer in the system.Maintainingthewatertempatorneartoyouraveragelocalannualtemperaturewill greatly minimize electrical consumption. This means that cold-wateraquaponicsis lesssuitedtotropicalorwarmerclimatesandis ideallysuitedtotemperateclimatesorcolder.

IMPORTANT

Theidealaquaponicsystemraisesafishspeciesthatcanthriveatawatertemperaturenearthelocalannualaverage,growsvarietiesofplantspecieswelladaptedtothelocalgrowingconditionsandmaintainsawatertemperatureandpHthatishighenoughtosupportgoodbacterialperformance.

pHpH (potential of hydrogen) is the acidity or alkalinity of a substance; 7.0 isneutral.Lessthan7.0isacidic,greaterthan7.0isalkaline.pHiscriticaltothehealth andperformanceof anaquaponic system. It is essentialyouunderstandtheprocessesinvolvedinmanagingpHeffectively.

ManagingpHisanotherbalancingactbetweenthedifferentbiologicalneedsin the system.The ideal pH is one that heavily favors the needs of the plants(generallybelow7.0)withoutbeingtoolowfor thefishandbacteria.Fishandbacteria prefer to be in water above 7.0 but are generally tolerant of mildlyacidicwater.Thereasonplantgrowthisheavilyweightedinthisconsiderationisthat the plants generate the vastmajority of the revenue, thus their rapid andvigorous growth without excessive detriment to fish or bacteria will greatlyincreaserevenue.

We have found the ideal pH to be 6.4 to 6.6, and we try to consistentlymaintainapHof6.5.

pHforthesystemisalwaysmeasuredinthesumpnearthepumpinlets.Thegoal is to measure the pH just before the water enters the fish tanks. A pHcontrollerthatcontainsbothapHmonitorandadosingpumpislocatedbesidethesumpandautomaticallyadjuststhepHasneeded.

The processes of nitrification and mineralization tend to constantly makewatermoreacidic(loweringthepH).Inmostcases,youwillneedtocompensateforthisbyslowlyaddinganalkalinechemicaltomaintainthepHatthedesiredsetpoint.However, in some locations, themunicipalorwellwatermayhaveahigh mineral content (known as “hard” water) due to it passing throughlimestone formations in the aquifer.The carbonates present in hardwaterwilltend to buffer the pH of the aquaponics system, keeping the pH fairly high(above7.0).Ifthelevelofcarbonatesintheincomingwaterishighenough,youmayfindthatyouneedtocontinuouslyadjustthepHdown.

Atourfarm,thesourcewaterisvery“soft”(lowalkalinity),soweonlyneedto adjust the pH up. pH is adjusted up by introducing potassium hydroxide(KOH or caustic potash) and calcium hydroxide (Ca(OH)2 or hydrated lime)throughtwoseparatemeans.

KOH,which is readily available in a concentrated liquid, isdosed into thesystemviathepHcontroller.Ca(OH)2,whichismostcommonlyavailableasafine powder, is added to the system by putting a sock full of it in theCombination Filter Box to slowly leach out. This method, though seeminglyinelegant, is highly effective. Never use sodium bicarbonate or sodiumhydroxideinanaquaponicsystem,asthesodiumcanbetoxictotheplants.

KOHandCa(OH)2areusedtoadjustpHbecause,atthelevelsneeded,they

are non-toxic to the fish, plants and bacteria and have the added benefit ofsupplementingcalciumandpotassium,importantplantnutrientsthat tendtobedeficientinmostaquaponicsystems.

IfyourwatersupplyisparticularlyhardandyouneedtoadjustthepHdown,use phosphoric acid (H3PO4). As is the case with hydroxides, at the levelsneeded,phosphoricacidisnon-toxictothefish,plantsandbacteriaandhastheaddedbenefitofsupplementingphosphorustotheplants.Inthiscase,youmayneedtoalsosupplementsmallamountsofpotassiumandcalcium,dependingonthe levels of theseminerals in your incomingwater. Phosphoric acid is dosedintothesystembythepHcontroller.

WaterQualityManagementWaterqualitytestsshouldbeperformeddailyandweeklyinordertomonitorthehealthofthesystemandmakeadjustments.Itiscriticalthatammoniaandnitritelevels be tested frequently as this is the only way to monitor the ongoingperformanceofthebiofilter.Mineralsthatareimportantforplantgrowthshouldbetestedatleastweeklytomakesurethattheyarepresentinsufficientquantity.

SeeChapter6foradetaileddiscussiononpHandwatermanagement.

AerationAllthebeneficiallifeinanaquaponicsystemrequiresoxygen.Fish“breathe”it,plants absorb it through their roots, andbacteria consume it in theirmetabolicprocesses.

IntherootzoneofDWCsystems,plantrootsarefullysubmergedinwatersotheonlyoxygenavailabletothemisdissolvedinthewaterandislimitedtoabout10ppmat15°C,andevenlessathighertemperatures.TheavailabilityofoxygenattherootzoneisoneofthelimitingfactorsinaDWCsystemandmaybethereasonwhycertainplants,suchasspinach,donotthriveintroughsbutdowell in towers. It is best to think of the root zone in a DWC system as airsaturatedwater.

InZipGrow™Tower systems,plant roots areheld in averyporousmediathathasavoid ratio (oropenspace)ofabout90% throughwhich thewater istrickled. Because the roots are not fully submerged as in aDWC system, the

rootsareabletoabsorboxygenfromboththewaterandtheambientairwhichcontainsfarmoreoxygen.Itisbesttothinkoftherootzoneintowersystemsaswatersaturatedair.

As the water falls through the tower media, it is broken into many finedroplets with a high overall surface area which enables oxygen in the air todissolveintothewater.Thismakesthetowersself-aeratingandnegatestheneedforamechanicalaerationsystem.

In DWC systems, there is no natural mechanism to create a large contactzone between water and ambient air which would allow sufficient oxygen todissolve into the water. Without supplemental aeration, all oxygen alreadydissolvedinthewaterwouldquicklybeusedupbythebiologicalactivityofthebacteria, plants and fish, and the entire systemwould suffocate in amatter ofhours.

Supplemental aeration is accomplished via air pumps called regenerativeblowers (we call them “aerators” throughout this book) that force ambient airthroughunderwaterdiffuserscalledairstones.

Air stones are porous silica and break up air into small bubbles. Smallerbubbles have a far greater collective surface area than larger bubbles. Moresurfaceareameansmoreoxygenisabletodissolveintothewater.Airstonesareplaced throughout the troughs, in the sump and in the CFB. They are neverplacedinthefishtanksasdoingsoimpedestheself-cleaningnatureofthetanks.

In the troughs,we recommend using one SweetwaterAS5 air stone undereveryraft.Thesestonesare3″×1″andhaveasuggestedflowrateof0.30CFMeach.ForthesumpandtheMBBR,werecommendusingSweetwaterAS15airstones(teninthesump,sixintheMBBR).Thesestonesare6″×1.5″andhaveasuggested flow rate of 0.50 CFM. You will also require MNPT x Barbconnectorsandairtubing.

Aerating the troughshas theadditionalbenefitofgentlyagitating theplantrootswhichpreventsexcessiveparticulateaccumulationon the roots.Aeratingthesumpservestwopurposes:tofullymixinthewaterreturningfromtheheatpumpand tohomogenize thechemicalsused forpHadjustments.Aerating theCFB vigorously agitates the MBBR and provides oxygen for the nitrifyingbacteria.

One aerator of sufficient size can easily supplement enough oxygen for

systemsaturation.Theproblemwithhavingonlyoneaeratoristhatthereisnobuilt-inredundancy.Inotherwords,ifyouraeratorfails(andlikeallmechanicalequipment, it eventually will), your fish will die in a few short hours as theoxygenisusedbutnotreplaced.

Therearetwooptionsforprovidingtherequiredredundancy:haveasecondbackup aerator onsite and/or connect the backupoxygen system to the aeratorviathemonitoringsystemsothatiftheaeratorfails,oxygenwillbesuppliedtothefish.

Airstoneactivelyaeratingthewater.NoticetheO-ringbumper.

Ifyouopttohaveabackupaerator,itcaneithersimplybeonsite,readytobeinstallediftheactiveunitfails,orthetwounitscanbeinstalledinparallelwithapressureswitchandrelaybetweensothatthesecondunitactivatesautomaticallyif the first fails. If you do not use an automatic standby aerator, or forgo abackupaeratorentirely,youmustuseamonitoringsystemandabackupoxygensystem to deliver oxygen to the fish tanks in case the aerator fails. See

MonitoringSystemandBackupOxygeninChapter5.The only downside to having two aerators onsite is the extra up-front

expense.Inthelongrun,thisismootasyouwillneedtoreplaceunitsovertimeandtheirlifespanswillnotbeshortenedbybeingonsite.Wecannotover-stressthe importance of maintaining aeration. We strongly suggest having twoidentical aerators onsite at all times, ideally installed in parallel so that thebackupactivatesautomaticallyinthecaseoftheprimaryaeratorfailing.

Todeterminethesizeofaeratorneededforyoursystem,addtheflowrateofallairstonesattheirsuggestedflowrate.

Ifusingourrecommendedquantityofspecifiedstones:

Troughs:

258@AS5stones×0.30CFM=77.4CFM

SumpandMBBR:

16@AS15stones×0.50CFM=8CFM

Total=85.4CFM

Thereforeyouwillrequireanaeratorcapableofdeliveringaminimumof86CFM@10″ofwater(thedepthof troughs).For thisexample,werecommendthe Sweetwater SST30 regenerative blower which outputs approximately 90CFMat10″depth.

PumpsLike the arteries in your bodymoving blood, the plumbing in your farmwillmove water throughout the system in a precise and controlled manner. Thesystem isdesigned tomovewaterwithin a specific rangeof flowat all times.Improperly designed systems can have water that moves too fast, which cancause poor ammonia oxidation and solids removal, or too slowly, which cancreatestagnationandlowoxygenlevels.

Water will be moved through your system via two parallel centrifugalpumps,thoughonlyonepumpwillbeoperatingatanytime.Acentrifugalpump

usesanimpellertomovewater.Mostmodernwaterpumpsareoil-less,meaningtheydonotcontainanythingthatistoxiciftheyphysicallybreak.Yourpumpsmustbeoil-less.

Thekeycharacteristicofapumpisitsperformancecurve:agraphpublishedbythemanufacturerthatshowsthevolumeofwaterthatthepumpcanmoveatagivenhead(resistance).Theterm“head”isusedtodefinetheamountofworkapumpmustdotoovercomegravity,verticalheightandfrictioninthepipe.

The“shut-offhead”ofapumpistheheightatwhichapumpcannolongermovewater throughthedischargepipe.Youcannotoperateapumpunder thisconditionasitwillburnout.

The “total head” is a cumulative total of: the height of the pump over thewaterlevel inthesump(calledthesuctionhead), theverticaldistancebetweenthepumpandthewaterinletstothefishtanks(calledtheverticalhead)andthefrictionlossesofeachpipeandfittingbetweenthepumpandthefishtanks.

Friction losses are due to the friction of thewater against the sides of thepipe;dynamiclossesareduetoturbulentflowcreatedbythebendsofindividualfittings.

The objective of the pumps is to fully replace thewater in each fish tankevery30–45minutes.Eachofthethree8′diametertankscontainsapproximately4,000 liters (or 4 cubic meters) of water, so the pumps must be capable ofmovingapproximately12,000litersofwaterevery30–45minutestoreplaceallwaterinthetanks.

Toproperlysizepumpsforyoursystem,youwillfirstneedtoknowthetotalheadandthedesiredrateofflow.Onceyouknowthesetwopiecesofdata,youcanselectpumpsbylookingatthepumpcurvepublishedbythemanufacturer.

Duetositespecificconditionsandfarmpreferences,eachsystemwillhaveadifferent total head. To discern the size of themain pumps required for yoursystem,calculatethetotalheadofyoursystemonceyourplumbingisinstalled.As with the aerators, this design calls for two identical pumps, each sized topower your system by itself. The rationale is again redundancy, as all pumpseventuallyfail.

Early on in our system,we learned this lesson the hardway.Our originaldesigncontainedonlyonelargepumpwhichworkedwellenoughuntilthedaythat a wayward frog found its way into our sump, was sucked up into the

impellerandcausedthepumptoseize.Beforewecouldremedytheproblem,welost an entire cohort of fish. It was this frog incident that led us to prioritizepumpredundancyandcreatethebackupoxygensystem(seeChapter5).

Thetwopumpsareinstalledinparallelwithvalvesthatalloweasyswitchingfromonetotheother.Thewaterflowoutputfromthepumpswillbemonitoredbythemonitoringsystemwhichwillinformyouifthewaterflowdropsbelowasetpoint.Optionallybutrecommended,youcaninstallaflowswitchandrelaybetween the two pumps so that if the active pump fails, the other willautomaticallyactivate.

Forourdesign,theminimumflowrequiredis270LPM,whichwillreplacethewater in the three8′ tanksapproximatelyevery45minutes.Themaximumflow rate is 400 LPM which will replace the water every 30 minutes. Werecommenda target flow rateof400LPM.Note that the flow rate canbe toohigh.Ifitismuchabove400LPM,thesolidsretentioncapacityoftheRFSwilldecrease,andhigherflowrequiresgreaterUVcapacity.

SeeChapter4fordetailsoncalculatingheadandsizingpumps.

TowerSystemPumpsIfyouareusingatowersystem,youwillneedoneormoreadditionalpumpstocirculatewater from the sump to the towers as part of a split system.A splitsystemcontains twoseparate loops rather than thesingle loopused inaDWCsystem.ThefirstloopismostlythesameasinDWC:sumptoUV,UVtotanks,tanks to Tank Manifold, Tank Manifold to CFB. From the CFB, rather thanflowing to the troughsas inaDWC, thewater returns to thesumpcompletingthefirstloop.

The second loop runs from the sump to the towers and back to the sumpagain.Use thesameprocess tocalculate the totalheadforboth loopsandsizeyourpumpsbasedontheirpumpcurves.Ingeneral,a5′towerrequiresabout20liters per hour, or⅓ of an LPM. For a 120′ greenhouse which can holdapproximately 1,100 5′ towers, the pump on the second (tower) loopmust beabletomove350–400LPM.

Effluent

Fishpoop.Alot.Thisisthemainsourceofeffluent(watercontainingwaste)inan aquaponic system. Secondary contributors include uneaten fish feed, algaeandplantdebris.Thesewastesmustbefrequentlyremovedfromthesystemoritwill rapidly overwhelm the nitrifying bacteria and create anaerobic zones,leading tohighammonia levels.Excessammoniawillquicklybecome fatal tofish.

Twobottlesizesofourbioactivefishfertilizer.

As discussed earlier in this chapter, our system employs four stages offiltration:thefishtanks,theRFS,andthefilterscreensandMBBRintheCFB.If using a tower system,youdonot require anMBBRas thematrixmedia ineachtowerprovidesampleBSA.

The combined four stages of filtration will successfully remove enoughsolids fromyoursystemtomaintainahealthyecosystem.Butwhat todowiththeeffluent?Thesimplestoptionistospraythecontentsontoalawnorfieldasagrassorhayfertilizerortofertilizeanorchardorgarden.

We recommend fermenting, bottling and selling it as a local organic

1.2.

3.

4.

fertilizer. Properly produced, your “waste” product will be one of the bestfertilizersintheworld,highlyprizedbyfarmersandgardeners.Wealsorecyclethefinishedfertilizerbackintooursystemtoprovideadditionalmineralstoourplants(seeChapter6).

Thefermentationprocessisactuallyquitesimple:

CollecteffluentintheWasteTank.WesuggestusingIBCtotes.WhentheWasteTankisfull,transfertheeffluenttoasettlingtank(anotherIBCtote).Leaveitundisturbedforadayortwo,allowingthesolidstosettletothebottom.Therelativelycleanwaterintheuppercolumnofthesettlingtankiscalledthesupernatant.Thesupernatantisstillveryrichinnitrogenandotherplantnutrients as well as beneficial bacteria. Drain the supernatant from thesettlingtankviaavalveabout⅓ofthedistancefromthebottom.Itcanbestoredinanothertankorusedimmediatelyforcropirrigation.Theconcentratedsolidsarethentransferredto50–60galfood-gradeplasticbarrels forbiodigestion.Weaim tohaveaconcentrationof25–50%solidsforbiodigestion.

The biodigestion, or fermentation, process is also known as liquidcomposting. In thisprocess, thebacteriacontained in theeffluent solutionwillbreakdowntheorganicsolidsintotheirelementalconstituents.Theseelementsare plant food of the highest caliber. To ensure optimum fermentation, werecommend keeping the mixture at 20–25°C (68–77°F). We use one 300Waquariumheater controlledbya thermostat in eachbarrel, andwe recommendwrappingthebarrelsinaninsulativejackettobuffertemperature.Youmustalsoaerate the mixture by using an aquarium air pump with an airstone in eachbarrel.Theairpumpneedstoputoutatleast0.5CFMat36″depth.

With good conditions, your effluent mixture will be converted into thehighestqualityfertilizerin1–3months.Togaugecompletionofthebiodigestionprocess,testitforammonia.Finishedfertilizerwillnothaveanyammoniainit.Oncecomplete,wesuggestsendingittoalabforamineralanalysiswhichcanbeincludedonalabelandisusefulforsales.Wesellourfertilizerin1Land4Lbottlesatfarmersmarketsandlocalgardencenters.

Wedonotpasteurizeourfertilizer;thus,itisstillfullofmicrobialactivity.If

notusedwithinafewweeks,itmayturnanaerobicandstarttosmell.Thiscanbe overcome by shaking the bottle and burping (opening) it. You can alsoincludeause-bydateonthebottle.

Alternatively,thefertilizercanbepasteurizedpriortobottlingtogetashelf-stableproduct.Wechoosenottodothisaspasteurizationisenergyintensiveandtheproductlosesallthebenefitsoflivemicrobialactivity.Weprefertotreatitas a “live”product and instructourcustomers touse itwithina fewweeksorburpregularly.

TheSumpThesumpisthelowestpointinthesystemandisboththebeginningandtheendoftheflowofwater.Waterispumpedoutofthesumptothehighestpointinthesystem—thefishtanks—beforeflowingdownstreamthroughthesystemviagravitybacktothesump.

Thesumpservesmultiplefunctions,anditsdesignandconstructionarejustas important to theoperationof thesystemasanyothercomponent.Thesumpacts as a reservoir for the collection of water returning from the hydroponicsubsystem. It also serves as amixing and conditioning vessel, awater qualitymonitoringstationandapumpstation.

Thevolumeofthesumpisimportant.First,itmustholdenoughwaterduringnormal operations to effectively mix and temper the return water from thetroughs and the return water from the heat pump. Second, it needs to haveenough capacity to handle the “drain down effect” in the event of a poweroutage.SeeDrainDownEffect.

In our design, the sump is a 4′wide by10′ longpit that is 4′ deep. It hasreinforcedwallsandislinedwiththesameLDPEthatisusedtolinethetroughs.A2×8collararoundtheperimeter,sittingontopofthereinforcedwalls,allowsmostoftheplumbing,airandelectricallinesintoandoutofthesump.Thecollaralso holds the sump lid above ground level and prevents dirt and debris fromfallingin.

Thesumplidshouldbeawell-constructedsolidplatformthatcanbeeasilyopenedforobservationormaintenanceandcanbelockedclosedforsafety.Thesumplid isavaluableworkingspaceforharvestingandwashingproducesoit

needstobeabletohandletheweightofpeoplemovingandworkingonit.Water returning from the troughs is plumbed through the east end of the

sump. The heat pump, located just outside the south wall of the greenhouse,drawswaterfromthesoutheastcornerofthesump,heatsorcoolsthewaterasneededandreturnsittothesumpdownstream(fartherwestinthesump).

Ifyou install acistern, its intakeand returnplumbingshouldbeconnectednearthemiddleofthesouthwallofthesump.

The sump isoxygenatedconstantlyvia air stones connected to the aerator.Theprimarypurposeofthesumpaerationistovigorouslymixall thewaterinthesumptoensuretemperatureisconsistentandthatthepHadjustingchemicalsarewellmixedbeforethewaterispumpedtothefishtanks.

pHadjustments aremade in the sumpby an automaticpHmonitoring anddosing controller (see Chapter 6). The controller is located near the UVsterilizersat thewestendof thesumpso that itsprobecanread thepHof thewaternear thepumpintakes.Theinjectiontubingthatcarries thepHadjustingchemicals from thedosingpumpshouldbesuspendedover thesump,near thewaterreturnlinefromthehydroponictroughs.Thiswillensurethechemicalsarewellmixedandimprovestheaccuracyofthedosingsystem.

TheDrainDownEffectInDWCsystems,thedraindowneffectoccurswhenthewaterpumpisshutofffollowingnormalsystemoperation.Typicallythisisbecauseofapoweroutageorpumpfailure.Thedraindowneffectisduetothefactthatwateris“retained”throughout the system by various restrictions such as pipe size, friction andsurfacetension.

Forexample,at theeastendofeach trough isapipe thatcarries thewaterfromthenorthside to thesouthside.Thispipe isapotentialbottleneck in theflow.Ifitisnotoversized,duringnormaloperationsthewaterlevelinthenorthsideswillbeslightlyhigherthanthelevelinthesouthsides.

A second example is the meniscus (the curve in the upper surface of thewater) thatoccursat the lipof the troughdrainstandpipeswhich isdue to thesurfacetensionofthewater.Boththetroughheightdifferentialandthemeniscusheight at the standpipe are increased at higher flow rates orwith smaller pipesizes.

1.

2.

3.4.

Although theseheightsare relativelysmall,whenmultipliedby thesurfaceareaofacommercial-sizedDWCtrough, theyequate toa fairly largevolume.This differential is not an issue during normal operations, but when a poweroutageorpumpfailureoccurs,alltheretainedwaterinthesystemwilldrainintothesump.Wecallthisthe“draindowneffect.”

Ifthesumpdoesnothaveenoughcapacitytohandletheextravolume,itwilloverflowandthelostwaterwillneedtobereplacedbeforethesystembecomesoperationalagain.

Therearefouroptionstopreventthesumpfromoverflowing:

Build a sump that is large enough to hold the drain down volume of thesystem.Oversizeallplumbingconnectionsinthetroughstominimizewaterretention(inlets,outletsandstandpipes).Useacisternconnectedtothesumpasanoverflowcollection.Useanautomaticstandbygeneratortokeepthesystemoperationalthroughapoweroutage(thiswillnotassistintheeventofapumpfailureunlessyoursecondpumpisinstalledtoautomaticallyengage).

WorkbenchThe workbench will be where you do all the major jobs for plants, notablytransplanting and harvesting.The area can be built to your own design, but itshould be a comfortableworking height (usuallywaist high) andmust have awaterprooftop.Theeasiestmethodofconstructionisusingstandardlumberandplywood that is sealed with a water-based, no VOC, non-toxic sealant. For atrough system, the table must be at least 4′6″ long and 2′6″ wide toaccommodatea2′×4′raft.Foratowersystem,thetablemustbeatleast8′longtoaccommodateplantinginto5′towers.

CisternAcisternisaveryvaluableandrecommendedadditiontoanaquaponicfarmforafewreasons:

1.

2.

3.

It can capture and store rainwater, loweringyour ecological footprint. It isespeciallyhelpful if you face seasonalwater restrictionsor simplywant todecreaseyourrelianceonmunicipalwater.Itcantemporarilystorewaterfromyoursystemwhileperformingrepairsormaintenance or while performing a treatment protocol for fish health (seeChapter8).Itcanbeusedasoverflowfor thesystemtopreventsumpoverflowduringdraindownevents.

Onourfarmweusean8,000-litercistern.

PowerConsumptionAquaponics ishigh-tech foodproductionand requireselectricity. Ifpossible,adedicated service of at least 100 amps to the greenhouse is ideal to bothguarantee adequate capacity and for ease of accounting. See Chapter 4 forelectricalinstallation.

I

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•

PrinciplesofSystemDesign

FYOUOPT TOBUILDOUR SYSTEMwith adifferentgreenhousedimension than36′×120′oryouopttouseadifferentsystemoralternatecomponentsfromthe

design in this book, you will need to create your own system design. If youchoose to design your own system, you should understand it is a complexundertakingandthattheconceptsandformulaspresentedhereareessentialbutonlyscratchthesurfaceofthesciencebehinddesigningasuccessfulaquaponicecosystem.Additionalresearchismandatoryfordesigningyourownsystem.

TheGoldenRatioofCold-waterAquaponicsThedesignof any sizeand shapeof anaquaponic systemstartswitha simpleratiowhichwecalltheGoldenRatioofaquaponics:Gf/m2/Day

WhereGfisthetotalgramsoffeedgivendailytothefishandm2isthetotalHydroponicSurfaceArea(HSA)insquaremeters.HSAisthetotalsurfaceareadevotedtoplantgrowth.ThepurposeoftheGoldenRatioistobalancethedailyamountof feed that isadded to thesystemwith thewaste removalcapacityofthesystemandnutrientdemandsofthegrowingplants.

Thecapacityofanaquaponicsystemtoremovewasteisdeterminedbytwofactors:Thecapacityofthebiofiltertooxidizeammonia(nitrification),whichisdeterminedbytheBacterialSurfaceArea(BSA).

The capacity of the hydroponic subsystems to assimilate nitrates(denitrification), which is determined by the Hydroponic Surface Area(HSA).

Nitrification is the process of oxidizing ammonia into nitrates by thenitrifyingbacteria.Denitrificationistheremovalandassimilationofnitratesbytheplants.Essentially,withtheGoldenRatio,youarebalancingthefeedinputwithnitrificationanddenitrification.

The Golden Ratio was developed at the University of the Virgin IslandsspecificallyforDWCsystemswhichgenerallyhavealowBSA/m2ofHSA(lessthan2m2ofBSAperm2HSA)without taking intoaccount theBSAofplantroots.TheplantrootscandoubletheBSAofaDWCsystem.

AlthoughtowersystemscanhavefargreaterBSA/m2(upto150m2ofBSAperm2HSA),bothsystemshaveasimilartotalHSAandthusasimilarcapacityfordenitrification.Accordingly,theGoldenRatioshouldbeusedtodesignbothDWCandtower-basedaquaponicssystems.

Cold-watervsWarm-waterAquaponicsPioneering studies at the University of the Virgin Islands concluded that theidealratioforanaquaponicssystemisabout60gramsoffeedpersquaremeterofHSAperday,or60g/m2/Day.

Thisappears toworkwell forwarm-water systemsoperatingatanaveragewater temperatureof25°C(77°F),but inacoldwatersystemoperatingat15–17°C (59–63°F), the nitrifying bacteria grow much more slowly, thus moresurfacearea(BSA)isrequiredforsufficientoxidationofammonia.Additionally,nutrientuptakeinplantsisslowerincolderwater,andthereforedenitrificationisalsoslower.Forthesereasons,considerablylessfeedshouldbegivenperm2ofgrowingareainacold-watersystemthaninawarm-watersystem.

IMPORTANT

TheGoldenRatioforcold-wateraquaponicsis25–35g/m2/Day,or25–35gramsoffeedpersquaremeterofHSAperday.

UsingtheGoldenRatioTheGoldenRatioensuresthatanaquaponicsystemisbalancedcorrectly.Therearetwoprimarywaystousethisratio,discussedbelowasStep1andStep2.

Step1startswithaknownHSAandusestheGoldenRatiotocalculatethedaily feed amount and the total fish biomass that can be hosted in the systembasedontherecommendeddailyfeedrateforthefishyouchoosetoraise.Feedratesforfisharealwaysspecifiedasapercentageofbodyweightperday.Youcanuse this figure (target fishbiomass) inStep2 todetermine theappropriatevolumeofyourfishtank(s)andthushowmuchwatermustbedeliveredtoeachtanksothatthewaterineachtankisreplacedevery30–45minutes.

Step1isusedwhentheinitialknownvariableisthesizeofthegreenhouseandthustheavailableHSAthatwillfitinit.Thisisthemostcommonstartingpointfordesigningasystem.

Step2startswitheitheraknownbiomass(targetamountoffishyouwanttogrow)orknowncombinedvolumeoffishtanks(usefulifyoualreadyhavetanksand want to design your system around them). You can then use Step 1 tocalculatehowmuchHSAyouwillneedandthushowbigyourgreenhousemustbe.

Step1Themost common application is to startwith the biggest greenhouse you canafford,fitonyoursiteandwanttooperate(forexample,youmayhaveahugepropertyandlotsofmoneybutnotwanttooperatealargefacility).Fromthis,determine the size of the hydroponic subsystem, and thus the totalHSA. In aDWCsystem, theHSA is the surface areaof the rafts. In a tower system, theHSAisbestdescribedas theareaof floorspacededicated to the towerarrays,notincludingthewalkways.

Forexample, inaDWCsystemina120′greenhousewith86′ troughs(perourdesign),weproducethefollowingequation:43(raftsperside)×6(sides)=258 (rafts) × 0.743 m2 (size of each raft) = 191.69 m2 (HSA) For ourcalculations,theHSAforourdesignis192m2.

We then use the formula to find the daily feed rate, following theGoldenRatio:25grams×192m2=4,800gor4.8kgoffeedperday30grams×192m2=5,760gor

5.76kgoffeedperday35grams×192m2=6,720gor6.72kgof feedperdayThis shows that theamountof feed thatcanbesafelyadded to the system each daywithout overwhelming the nitrifying bacteria orallowing nitrate levels to rise excessively is 4.8 kg to 6.72 kg. With thisknowledge,wecan figureout the total fishbiomass thatcanbegrownon thisamountoffeedbasedonthedailyfeedrateforaspecifiedspeciesoffish.

Rainbowtrout,whichweraiseinoursystem,consumeanaveragedailyfeedrateof1.3%ofbodyweight(seeChapter8),therefore:@25g/m2/day:4.8kg/0.013=369kgtotalbiomass@30g/m2/day:5.76kg/0.013=443kgtotalbiomass@35g/m2/day:6.72 kg / 0.013 = 517 kg total biomass Thus after calculating the range offeeding ratios (from25–35gperm2 per day),weknow thatwehave a targetbiomassrangeof369kgto517kg.

The next step is to calculate how to divide the total biomass intomultiplecohorts.Thiswouldbesimpleifjustusingonetankandgrowingonecohortatatime. Unfortunately, raising single cohorts is not acceptable in an aquaponicsystem as it is critical the system be consistently loadedwithin its range: toolittle fish biomass will not adequately feed the bacteria and plants, too muchbiomasswilloverwhelmthebacteriaandharmorkill thefish.Asinglecohortsystemwouldbeseverelyunderloadedwhen the fishare fingerlingsandcouldbeoverloadedwhenthefisharemature,dependingonhowlargeyourfishgrow.

Toensureaconsistentlybalancedsystem,fisharegrowninmultiplecohortsof different sizes in separate fish tanks, andwhen the system is fully loaded,smallbatchesareharvestedfromtheoldestcohortevery1–3weeks.

WecannowuseStep2todeterminehowmanyfishshouldbeineachcohortwhilestayingwithintheGoldenRatio.

Step2UseStep2ifyoualreadyknowthebiomassrangeforyoursystem,orthesizeoftanks you want to use, or to ensure that your design has sufficient HSA tosupport your biomass range. Continuing our calculations from Step 1, theprocessisasfollows.

Our design uses three 8′ tanks, each with a volume of 4.2 m3. Therecommendedmaximumstockingdensity is60kg/m3, thereforeeach tankcan

carryamaximumof250kgoffishattheirtargetharvestweight:60kg×4.2m3

=250kgmaxbiomass (roundeddown from252kg)Fish canbeharvested atdifferentweightsfordifferentmarkets.Ifthetargetharvestweightforeachfishis1kg,youshouldstockeach8′tankwith250fish.Ifthetargetharvestweightis.5kg,stock500fishpertank.Consideryourpotentialmarketswhendecidingontargetharvestweight.

Let’s assume that 1 kg is the target harvest weight and that you will berestockingeveryfourmonthswith250fingerlingsat10–12cmlongandabout10–20 g each, which is what we do at Raincoast. At 15°C (59°F) watertemperaturewith idealwaterand feedconditions, rainbow troutarecapableofgrowing3cmpermonth.Ifthefishstartatanaverageof12cmlongwhentheyenterthesystem,thenafter4monthstheyshouldaverage24cmlong:12cm+(3cm×4months)=24cm

Theaverageweightoffishismathematicallyrelatedtotheirlength,usingaformulacalledtheConditionFactor(CF).TheCFofrainbowtroutundernormalconditions is1.11.Youcanpredict theaverageweightof thefishatanygiventimeusingthisformula:Weight(g)=CF×(length[cm])3/100

In our example, the estimated average weight per fish after 4 months ofgrowthis:Weight=1.11×(24)3/100

Weight=1.11×13,824/100

Weight=153gramsperfish

After8months:

Weight=1.11×(36)3/100

Weight=1.11×46,656/100

Weight=517gramsperfish

After12months:

Weight=1.11×(48)3/100

Weight=1.11×110,592/100

Weight=1.2kgperfish

With these calculations, we can determine the total biomass per tank atdifferentstages:Tank1(4months):250fish×153geach=38kgTank2(8months):250fish×517geach=129kgTank3(12months):250fish×1.2kgeach=300kgTotalfishbiomass=467kg

Nowwe have a snapshot of the total fish biomass estimated to be in thesystem when operating at full capacity. When the system is running at fullcapacity,youshouldbeharvestingfishonaregularbasisfromtheoldestcohorttokeepthetotalbiomassofthesystemwithintheacceptablerange.Accordingly,thetotalbiomasswilloftenbelessthanthemaximumcalculatedhere.ACohortLogforeachcohortoffishwillhelpyoukeeptrackofthebiomassineachtankatanygiventime,andtheselogswilltellyouhowmuchfeedshouldbegiventoeachtankdaily.FishSampleLogsandCohortLogsarecoveredinChapter11.

A total biomass of 467 kg is within the target range of 369–517 kg andwithintherangeoftherecommendedGoldenRatio:467kg×1.3%(dailyfeedrate)=6.07kgfeedperday

6.07kg/192m2HSA=31.6g/m2/day

Byusingtheformulasgivenabove,wedeterminedthatwith192m2ofHSAthesystemcancarry467kgoffishandthattherequireddailyfeedinputof6.07kgiswellwithin theacceptablerangeof theGoldenRatioof25–35g/m2/day.Wealsoknowthateach8′tankcancarryacohortof250fishwithoutexceedingthemaximumrecommendeddensityof60kg/m3.

Asafurtherexercise,wecanusetheGoldenRatioandthedailyfeedamounttocalculate theminimumandmaximumHSAand thus thenumberof rafts asfollows:Minimum:6.07kg/35g=173m2HSA=232rafts=78′troughsMaximum:6.07kg / 25g = 242 m2 HSA = 325 rafts = 108′ troughsA Note on TowerSystemsThesedesignprinciplesapply tobothDWCand towersystems: the feed inputand ammonia generated needs to be balanced with the system’s capacity toremove nitrates before they build up to levels toxic to the fish. The majoradvantageofZipGrow™Towers,whichuseamatrixmedia,isthattheyhaveamuchgreaterBSApersquaremeterofHSA.Theyarethereforemoreforgiving

of mistakes like overfeeding or infrequent cleaning of filters because theyconvert theammonia tonitratesmuchmorequickly thanDWCsystems.Othertypesoftowersystems,suchasthosefilledwithgravel,haveamuchlowerBSAthanZipGrow™Towers.

AFinalDesignNoteIfyouopt todesignandbuildanaquaculture system that is amajordeparturefromthedesignpresentedinthisbook,wewishyouthebestofluck.Designingafishculturesystemthatwillkeepyourfishnotonlyalivebutthrivingwillbethemostchallengingandscientificallycomplexpartof thedesign.Beforeyouembarkonthatjourney,wehighlyrecommendthatyoureadandunderstandthebook Recirculating Aquaculture by Timmons & Ebeling (3rd Edition, IthacaPublishingCompany,2013).Itisthedefinitivetextonrecirculatingaquaculturesystems and likely contains everything you need to know about keeping yourfishalive. It isahighly technicalbook,andwehave justscratched thesurfacehere.Itevenhasachapterspecificallyonaquaponics.Whetheryoudesignyourownsystemorfollowourdesign,werecommenditasareferencebookforallaquaponicfarmers.

I

ConstructingtheRCASystem

N CHAPTER 2 we covered all the major components and elements of ourdesign. Additional components are in Chapter 5. This chapter contains the

literal nuts and bolts of constructing and installing the system, from sitepreparationtobeingreadyforwatertoflowthroughthesystem.

IMPORTANT

Unlessyouareaprofessionalcontractorwithconsiderableconstructionskillsandexperienceworkingwithvarioustradecontractors,westronglysuggestyouhireageneralcontractor(GC)tooverseeyourconstruction.Agoodruleofthumbisthis:ifyouwouldhireaGCtobuildahouse,youshouldhireonetobuildyourgreenhouseandaquaponicsystem.Manyoftheinstructionsweprovideinthischapteraregeneralinnature,andtheconstructionand/orinstallationmayrequireaprofessionalbuilder.Everysitewillhaveitsownuniquedemands.Wecannotcoverthemyriadcontingenciesandproblemsyouwillencounterthatarespecifictoyoursiteandproject.Foralltasks,followyourlocalbuildingcodeasapplicable.

Alwaysfollowmanufacturers’ installationandoperationinstructions.Ifourinstructions or recommendations contradict a manufacturer’s, follow themanufacturer.

Thegeneralorderforconstructionis:

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SitePreparationGreenhouseConstructionElectricalInstallationSumpConstructionWasteTankExcavationTroughConstructionTroughLinerInstallationTroughPlumbingInstallationAquacultureSubsystemInstallationPumpandPlumbingInstallationHeatPumpInstallationCisternInstallationSeedlingTableConstructionWorkbenchConstructionAerationInstallationCoolerInstallationGerminationChamberConstruction

SitePreparationWehavepreviouslycoveredthevariousconsiderationsforchoosingapropertyandbuyingagreenhouse.Bythispoint,weassumeyouhavesecuredaproperty,ordered a greenhouse and obtained all necessary permits to build. In securingyourproperty,youwillhavechosenyourspecificgreenhousesitebasedonthefactorscoveredinChapter2.

Thefirstorderofbusinessistoexcavatethesite.Haveanexcavatorlevelthegroundbyremovingallturf,topsoilandcompostablematter,andscrapedowntoundisturbed,compactedearth.Thearearequiredisaminimumof10′largerthanyourgreenhouseonallfoursides(140′×56′fora120′×36′greenhouse).Aftertheinitialexcavation,usea laser level toconfirmthat thearea is level towithinafewinches.Alllargerocks,stumpsordebrismustbefullyremovedifexposedabovethislevel.

GreenhouseConstructionIf you are buying a new greenhouse, it will come with detailed installationinstructionsaswellasallrequiredhardware.Followtheinstructionstotheletter.

If you are buying a usedgreenhouse, oneof the biggest downsides is it islikelythatitwillnotcomewithinstallationinstructions.Accordingly,youmusteitherbemeticulousindocumentinghowthegreenhouseistakendownsoyoucanreversestepstoreinstallit,oryoushouldhireprofessionalinstallers.

FoundationInstallationMostgreenhouseswillrequireeitherapierfoundationorastemwallfoundation.Apierfoundationcostsless(lessconcrete)andiseasiertoinstallasthepiersdonot require forms or framing. The foundation posts are set into the freshlypoured concrete piers to support the arches. The arches will bolt onto thefoundationposts.

Using batter boards and string lines, lay out the piers per the greenhousespecs.Markthestringlinewiththepositionofeachfoundationpostthatwillbesetintotheconcretepier.Usinganauger,digthepierholestothediameteranddepthspecifiedby themanufacturer.Fill theholeswithconcreteandplace thefoundationpostsastheconcretesets,usingstringlinesasaguideforaccuracy.

Digaperimeterdrainaroundthegreenhouse.Ifthereisalocalbuildingcodethatapplies,followthecode.Theperimeterdrainmustbeatleast2′deepand2′awayfromthepiers.UseSchedule40perforated4″PVCthatdrainsawayfromthe greenhouse.Backfill the perimeter drainwith 12″ of drain rock, cover therockwithlandscapefabrictopreventdirtcloggingthepipe,thenfill togroundlevelwithgravel.

Foundationinstallationwithstringlinesandbatterboards,readyforconcretepiers.

ArchesInstallationTheconcretepiersshouldbeat leastsevendaysoldprior to installationof thearches,sothattheconcreteismostlycured.Werecommendhavingatleastfourstrong people onsite for this job. Follow the manufacturer’s instructionscarefully.

In general, the procedure is to construct each archwhile it is lying on thegroundandthenstanditupusingmuscleandrope.Ifpossible,rentascissor-liftoratelescopingforklifttoassistwithstandingupthearches.

The arches are shipped in halves and bolted together onsite with crossbraces.Startatoneendofthegreenhouseandworkyourwaytotheotherend,standinguponearchatatime.Afteryouinstallthesecondarchtoitspiers,boltittothefirstwiththesuppliedpurlins.Afteryouinstallthethirdarchtoitspiers,bolt it to the second, and so forth.Once all arches are in place, add thewindbracing, which will greatly increase structural integrity. When complete, thearcheswillresembletheribsofalargemetalliccreatureoranupside-downboat.

Beforebuildingtheendwalls,confirmthatyourfishtankswillfitthroughthelargeslidingdoors.Iftheywillnotfit,movethetanksintothegreenhouse.

Greenhouseframe.

EndwallInstallationThe endwalls of greenhouses vary considerably. Follow the instructionscarefully. Part of the installation will be installing the power vents, fans anddoors that are housedwithin the endwalls. Plan outwhere the electrical, data,waterandpropaneserviceswillenterbelowtheendwallsandinstallconduitsforthem.

Typically,polycarbonateendwalls(aswerecommend)are installedbyfirstconstructing a steel framework of vertical posts and horizontal braces thensecuringthesheetsofpolycarbonatetotheframe.Thewallframingandbracingwillvaryfromgreenhousetogreenhousedependingonthelayoutofdoors,ventsandothercomponents.

Afterthepolycarbonateissecuredtothewall,metalrainflashingisfitoverthejointbetweentheroofandendwall,andthenC-channeloranothersystemforsecuringtheroofcoveringisinstalledovertheflashing.

Once the endwalls are installed, install baseboards around theperimeterofthegreenhouse.

CoveringInstallation

Next,installthegreenhousecovering.Ifyouarebuyinganewgreenhouse,youshould receive detailed instructions on how to install your chosen covering.Followtheinstructionscarefully.

Polycarbonateendwall.

Ifyouareusingdouble-layerpoly, install thechannelsorothermechanismthatwillsecurethesheetstothegreenhouse,typicallymetalC-channelrunningaround theperimeter.Thepoly is tucked into thechannelandawireorclip isusedtolockitinplace.

Polywill comeona largehollow-core roll andcanbe installedbyvariousmethods.Theeasiestistorolloutbothlayersonanothersheetofcleanplasticonthegroundalongonesideofthegreenhouse.Throwthreeropesovertopofthearches,oneneareachendwallandoneinthemiddleofthegreenhouse.Attachtheropestothecornersandmiddleofthepoly,makingsureeachropeissecuredtobothsheetsatthesametime.Withonepersononeachrope,slowlydragthesheetsofpolyoverthegreenhouse,takingcarenottotearthemonsharpobjects.

Oncethesheetsarestraightenedoutandfreeofwrinkles,theycanbesecuredtotheC-channelandanyexcesstrimmed.

Roll-upSidesInstallationRoll-up sides consist of a tube running the length of the greenhouse, aroundwhichthebottomedgeofdouble-layerpolyiswrappedandsecured.ThetopofthepolyissecuredtoC-channelthatrunsalongthesidepurlin,typicallyaboutsixfeetaboveground.Agearedcrankinghandleatoneendofthetubeisusedtoroll-upthe tubeandboth layersofpolywith it. In thewinter,bothendsof theroll-up sides are secured to C-channel on the two end arches, and the spacebetween the layers of poly is inflated using the same blower that keeps thecoveringinflated.

HangingComponentsInstallationMount all items that will be hung from the cross braces of the greenhousearches.This includes thepropaneheater,circulationfansandhangingsupportsfor the HID lights (the lights will be installed later). Follow the installationinstructionsfortheheaterandthecirculationfans.

CirculationFansInstallationThe circulation fans should comewith a specific layout and direction of flowthatmaximizescirculationandmixtureofair. Ingeneral, theairwill flowinacirclearoundthegreenhouse.Our80′greenhousehasfourcirculationfans.

HeaterInstallationPrior to installingtheheater,wesuggestconsultingwiththegasfitteryouwillbe using to run your propane line. Discuss placement of the heater, ventingoptions, where the propane tank will sit and the path the gas line will takebetweentankandheater.

Ifyouareusingadouble-polycovering,youmustventthroughtheendwallclosest to the heater. Our heater is located in the northwest corner above theSeedling Table. As discussed in Chapter 2, it is advantageous to use rigidpolycarbonatefortheendwallsasitallowslinesandductstopassthroughneatly

1.

2.3.

4.

andeasily.Ifusingapropaneorgasheater,youwillrequirealargestoragetankonsite.

Thesecaneitherbepurchasedor rentedonanannualbasis from thecompanythat will supply your propane. Ours costs about $10 per month to rent. Theservicecompanycomestooursiteandfillsitonrequest.

HIDLightInstallationSupplementarylightwillberequiredasdiscussedinChapter2.Weuse1000WHPS(HighPressureSodium)lightsthathavelamp,ballastandreflectorinoneintegrated unit.Our lights are on lightmovers,with each bulb responsible forcovering approximately a 20′ long span of each 8′ wide trough. For a 120′greenhousewith86′troughs,youwillneedfourlightspertrough,twelvelightstotal.

There are numerous DIY methods for hanging your lights. For a troughsystem,thelightswillmovedirectlyoverthemiddlewallineachtrough.Foratowersystem,installlightsasspecifiedbythetowermanufacturer.

Oursimplesystemforhanginglightsis:

Hang chains from the cross braces over the center of each of the threetroughs.InstallS-hooksatthebottomofeachchain.Hangwood2×3s(or2×4s)onedgeforthelengthofeachtrough,usingeyescrewsinthetopedgefortheS-hooks.The2×3scanbereplacedwithmetalifyouprefer.Makesuretheeyescrewsareratedtohold100lbs.Prior to hanging, screw the lightmover tracks into thebottomedgeof the2×3s.Makesuretoaccuratelyaligntheendsofthetrackstoensuresmoothmovementofthelightmovers.

Atthispointinconstruction,theonlymandatorystepistohangthechains,as this ismore difficult once the troughs are installed. Steps 2–4 can be doneeithernoworlaterwhenyouinstallthelights.

WeuseandhighlyrecommendGavitaPro1000WDEunitsforthetroughs.WealsouseandrecommendLightRaillightmovers.

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ElectricalandInternetInstallationUnlessyouareanelectricianbytrade,youshouldhireanelectrician.Improperlyinstalling any other component in the system can lead to crop failures, deadcohortsandlostincome,butimproperlyinstalledelectricalcankillyou.Followcodeasapplicableandlistentotheadviceofyourelectrician.

For ease of installation, the electrical cables should be run from themainelectrical panel to their outlets before installing the troughs or fish tanks. Themainserviceconnectiontoyourgreenhousewillruneitheroverheadfromapolenear thegreenhouseor underground to themain electrical panel.However thepowerisbroughtintothegreenhouse,westronglysuggestrunningcablesinthegreenhouseoverheadinthearchesinsteadofburyingthem.UsePVCelectricalconduit or as specified inyour electrical code.All conduits, connectionpointsandjunctionboxesshouldbemoisture-proofPVC,andalloutletsmustbeGFCI.

The location of themain panelwill depend on local codes andwhere themainpowerforthepropertyislocated.Ifyouopttoinstallthepanelinsidethegreenhouse and code allows this, the box should be installed on an endwall.Mostofthecircuitswillbeatthewestendofthegreenhouse,butthisendwallwill also become very crowded.Note that if you install the panel on the eastendwall, you will likely need to oversize some of the cables to account forvoltagedropduetothelengthofthecircuits.

Ourpowerentersviaaburiedcablefromtheeast.Ourpanelislocatedontheinsideoftheeastendwall,andthecablesrunoverhead.

Thefollowingaresuggestedcircuitslistingcomponentsthatcanbegroupedtogether or components that require dedicated circuits. In some cases, thesesuggestionsmay not be possible if the voltage for the component is differentthanshownhere(e.g.,ifthewaterpumpsare240vandtheUVunitsare120v).

WaterpumpsandUVsterilizersAerationblowerTroughHIDlighting(thismayrequiremultiplecircuits)SeedlingHIDlightingHeatpumpWalk-incoolercondensingunitWalk-incoolerevaporatorandGerminationChamber

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Auxiliaryoutdoorpower(washingmachine,effluentpump,etc.)GreenhousecirculationfansandpropaneheaterEndwallventilationfansandpolyinflationblowerPlugoutletsbystainlesssinkandemergencyoxygensystemPlug outlets by sump for water monitoring equipment (pH controller,Web600)PlugoutletsbyworkbenchareaTwo plug outlets on the east endwall (one at the end of each middlewalkway)

InternetInstallationThe monitoring system (see Chapter 5) will likely require a stable internetconnection to send alarms.We highly recommend running Cat5e cable ratherthan trustinganyWi-Fi system. Inmost cases, the ideal time to run theCat5ecableisinaconduitinthesametrenchastheburiedpowercable.

SumpConstruction

IMPORTANT

Safetyaroundthesumpisamajorconcern.Yoursumpwillbea4′deepholefilledwithwater.Ifachildorpetweretofallin,theycouldeasilybecometrappedanddrown.Bemindfulofthisandtakeprecautionsduringconstruction.Itismandatorythatyouhavealockinglidonyoursumponceconstructed.

Our design calls for a sump that is 4′ wide, 10′ long and 4′ deep. Thesedimensions are all exterior,meaning once you have built the sumpwalls, theinteriordimensionswillbeabout3.5′wide,9.5′ longand4′deep,witha totalvolumeof170cubicfeetor4,800liters.

If your site does not allow the sump to be a depth of 4′, compensate byextending the length but not the width. Expanding the width towards the

greenhousewallmaycompromisetheadjoiningpierfoundations.Expandingthewidthtowardsthefishtankswillcompromiseyourwalkingandworkingspace.Consider also the dimensions of the material being used to line the sump. IfusingLDPEasaliner,thedepthandwidthofthesumparelimitedtothesizeoftheliner.

SumpConstructionUsingnon-toxicspraypaint,markaspot17′fromthewestendwalland2′fromthesouthsidewall.This is thesouthwestcornerof thesump.Fromthiscorner,markoutarectangle4′tothenorthand10′totheeast.Double-checkthelayoutissquarebymeasuringbothdiagonals.

Excavatetheholeatleast4′by10′by4′deepatallpoints.Filltheholewitha 2″ layer of bedding sand to prevent sharp rocks frompiercing the liner andtamp it flat.Youwillalsousea2″ layerofbeddingsandas thebase foryourtroughs, fish tanksandcistern.Youcansavedelivery feesbycalculatingyourtotalsandrequirementandorderingonlyonce.

Thewallswillneedtobeshoreduptopreventcollapseovertime.Thereareseveral methods to do this, including treated timbers and plywood, pouredconcretewallsorburyingarigidpolytank.Itisnotacceptabletosimplylineabaredirthole.Usingconcreteorrigidpolyhastheadvantageoflongevitybutisveryexpensiveandin-wallserviceconnectionsareverydifficult.

Ourrecommendedmethodistoconstruct4′highstickframeswalls,similarto those used in houses, using treated 2×3s sheathed on both sides with ½″treatedplywood.Thestudsshouldbeon12″centers.Useonlyexteriorscrewsasfasteners.

Woodinaconstantlymoistenvironment(suchasincontactwiththeground)will eventually rot. Expect buried treated lumber and ply to last 5–10 yearsbeforeneedingrepairorreplacement.Expectnon-treatedlumberandplytolast2–5 years before needing repair or replacment. Also note that using treatedlumbermaycompromiseorganiccertification.

Priortoinstallingthewalls,linethesumpwitha6milpolyvaporbarriertoprevent wood deterioration. Do this even if you are using treated lumber andplywood.

Sump.Sideview.

Install thewalls in the sump and fasten them together at each cornerwithexteriorscrews.

Linethesumpwith20milLDPE.Thisisthesamematerialyouwillusetoline the troughs, somake sure to order enough for both. If you choose to useLDPEto line theSeedlingTableorworkbench, include theseamounts inyourorderaswell.Youmustusealinerregardlessofthetypeofwallsyou’vebuiltinyour sump, including concrete. Concrete is not waterproof and will leachhorriblethingsintoyoursystemwater.

Wrapthelineroverthetopofthewallsbeforeinstallingthecollarsothatthelinerispinchedbetweenthem.

Ontopof thewalls, fastenacollarof2×8 lumberonedge.Thecollarwillsupportthelidandraiseitabovetheground,preventingdebrisfromenteringthesump.Thetopofthecollarshouldbe3″abovethefinalgroundlevel(includinggravel),soplantheheightofthewallsaccordingly.Priortoinstallingthecollar,

applytwocoatsofepoxyresintoallsixsidesofeachboardandallowthemtocure.

The sumpwill be a constantlywet area. All exposedwood, including thecollar,lidsupportjoistsandlid,mustbesealedwithtwoorthreecoatsofepoxyresin.Paintaloneisnotsufficient.

Once they have been coated and cured, install horizontal joists across thewidth of the sump that will support the lid. Install a joist every 2′. The joistnearest the west end of the sump should be a double joist, as one side willsupportthesumplidthatopensandtheotherwillsupportafixedplywoodcoveraroundthepumpintakes.

Install thesumplidwithnon-rustinghingesofyourchoosingandthefixedplywoodcoverwithexteriorscrews.Thesimplestandrecommendedmethodforthelidistouseasinglesheetof¾″untreatedplywood,waterproofedwithepoxyresin.Applytwocoatsofresintothesumplidandfixedplywoodcovering.Werecommendthreecoatsforthetopofthelidasitwillbewalkedon.Addasmallamountofsandwhileapplyingtheresintothelasttwocoatsonthelidforanon-slip top.Optionally for aesthetics, you can paint the top of the sump lid afterapplyingresinwithawater-based,noVOC,non-toxic,non-anti-microbialpaint(thesamepaintusedtopainttherafts).Installalockinglatchonthesumplidforsafety.

Inatowersystemwithtwosplitloops,additionalsumpdesignconsiderationis required toensureeffectivemixingof thewater fromboth loops. Install thefish tankpumpsat the southwestcornerand the4″ return lineat thenortheastcorner(sameasDWCdesign).Install towerpumpsat thesoutheastcornerandthereturnlineatthenorthwestcorner.

Sump.Topviewwithcoverremoved.

Ifpossible,allscrewsusedshouldbestainlesssteel.Evenexterior(coated)deckscrewswillrusteventuallyiftheyareconstantlyexposedtomoisture.Thisappliesforallconstructionbutisparticularlyimportantinthesump.

IMPORTANT

Thetwopartsofanepoxyaretheresin,whichisnon-toxic,andthehardener,whichisverytoxic.Ifthetwopartsarenotmixedinproperproportion,thereisapossibilityofuncuredhardenerinthemixwhichcanleachandbetoxictofish.Makearesin-richmix(moreresinthanhardener)toavoidthisproblem.Neverusepolyesterresin.Thisisimportantforallepoxyapplications.

WasteTankExcavationWesuggestusingoneormorestandard1,000-literIBCtotesforwastecollectionthatwillbelocatedatleast20′outsidethegreenhousetothewest.Ifthereisnoelevationchangeatyoursite,youwillneedtodigawastecollectionpit.ThepitshouldbebigenoughtohousetheWasteTankswiththeirtopsbelowtheoutletlevel of the bottom of your fish tanks, including a 1″ drop every 10′ of pipelength.

Plumbingforwastecollection.NotetherequirementforelevationdroptoWasteCollectionTanks.

Wesuggestdiggingthepitwhileyouhaveanexcavatoronsite.However,donot install the Waste Tanks yet. This will be done after the undergroundplumbing is roughed in. If in doubt about howdeep to dig the pit, dig it 2–3′deeperthanyouthinkisneeded.Packabaseofgravelforthetankstositonand,ifpossible,createadrainagetrenchforwhentheyinevitablyoverflow.

TroughConstructionGroundPreparationThefirsttaskistopreparethegroundinthe90′-longareawherethetroughswillbe located (86′ for troughs plus a 4′ walkway at the eastern end of thegreenhouse).Thegroundmustbeflattenedandcompactedtowithin¾″overthewidthand lengthof the area. It isvery important that the areabe level to thisaccuracyor thetroughswillendupwarped.Spread2–3″of¾″crushedgravelovertheareaandcompactitwithaheavyplatecompactoruntilitisasflatandhardaspossible.Useasurveyor’slevelforaccuracy.

Lay out the rough location of the troughs on the ground bymarking theircorners with a water-based spray paint. Start by lining up the middle of the

1.2.3.4.5.

centertroughwiththecenterofthegreenhousebyhangingplumbbobsfromthecenterofthecrossbracesontwoarches,oneateachendofthetrough.Markthelocation of themiddlewall of the center trough, thenwork outward from thecenter,measuring andmarking the aisles and the corners on both ends of thetroughs.Finally,markthemiddlewalllocationsofthetwooutertroughs.

Theoutsidedimensionsofthetroughsare86′8″longand8′9″wide.Ina36′wide greenhouse, the walkways are 29″ wide. In a 40′ wide greenhouse, thewalkwaysare41″wide.Theeasternedgesare44″fromtheeastendwallofthegreenhouse.

Atthistimeyourobjectiveistomarkthelayoutclosetothefinalpositions,butyoudon’tneedtobeprecise.Oncethewallsofthetroughsareconstructedandintheirapproximatelocation,stringlinesareusedtoaccuratelyplacethemintheirfinallocationandsquarethem.

TroughConstructionEachofthefivewallsofatroughis13″high.Thelengthofthetwosidewallsandonemiddlewallareeach86′4″.Thetwoshorterendwallsare8′9″each.Allwallsareconstructedofstandard½″plywoodand2×3s,exceptthebottomplateswhichmustbe treated2×3sorstandard2×3sstainedwithawoodpreservativepaint.Werecommendpressuretreatedforthebottomplates.

Troughconstructionconsistsofthefollowingsteps:

Constructing6sidewalls,3middlewallsand6endwallsAssemblingthewallsFinalplacementofthetroughsTroughlinerinstallationPlumbinginstallation

SideandMiddleWallConstructionConstruct allwalls in the approximate location theywill be positioned so thatthey can be simply stood up and screwed together. Do not attempt to moveconstructedwallslongdistancesastheyareveryheavyandawkward.

Tobuildthesideandmiddlewalls:

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Layoutnine10′2×3s,endtoend.Cutthefirst2×3to76″.Thiswillbethetopofthewall.Layoutasecondrowofnine2×3sparalleltothefirst.Cuttheninth2×3to76″.Thiswillbethebottomofthewall.Cutting the opposite ends to 76″ will stagger the butt joints. This is veryimportant.Cut8″piecesof2×3blockingandplaceatbothendsandateverybuttjointonboththetopandbottomplates.All2×3sintheframewillbeonedge.Fastenall2×3stogetherusingexteriorscrewstoassembletheframewhichshouldbe13″tallby86′4″longwhencomplete.Cutsheetsof½″plywoodlengthwisecreatingfour12″by86″piecesfromeachsheet.Don’tworryabouttheslightlossofwidthduetothesawkerf.

Troughsidewallconstruction.

IMPORTANT

Theplywoodisontheinsideofeachsidewall.Itiscriticaltoleavethe1″gapatthebottomoftheframesothat,whenstoodup,itwillbetowardsthemiddleofthetrough.Ifyoudotheopposite,youwillhavetospinthewalllengthwisewhichmayproveimpossible.

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Sheaththe2×3frameswiththepiecesofplywoodontheinsideoftheframe,aligningtheplywoodwiththetopedgeofthe2×3framesothatthereisa1″unsheathedstripalongthebottomedgeoftheframe.Useexteriorscrewsandavoidhavingjointsintheplywoodlineupwiththejointsinthe2×3.Repeattheframingandsheathingprocesseightmoretimesfortherestofthelongwalls.Themiddlewallsareconstructedexactlythesamewayasthesides,exceptitdoes notmatterwhich side the plywood is on.You do not need to sheathbothsidesofthemiddlewall.

The1″unsheathedgapon thebottomplatesserves twopurposes:plywooddoesn’ttouchthegroundsoitdoesnotneedtobetreated,andthegapwillserveasadepthandlevelguidewhenyoufillthebottomofthetroughwithsand.

EndwallConstructionTheendwallsare105″long.Theframesarebuiltinthesamemannerasthesideandmiddle walls: 13″ high frames constructed from 2×3s with bottom platespressure treated and12″ highpieces of½″plywood.Theremust be a vertical2×3centered in themiddleof each endwall inorder to fasten it to themiddlewall.Donot sheath theendwallsat this time; this isdoneafter thewallshavebeenfastenedtogether.

AssemblingtheWallsForeachofthethreetroughs,youshouldnowhavetwolongsidewallswithplyontheinnersides,onelongmiddlewallwithplyononesideandtwoendwallsthatareframedbutnotyetsheathed,allwith1″unsheathedatthebottom.

Confirmtheroughlayoutforeachtroughperthepreviouslymademarkingssothatonlyminoradjustmentsarerequired.Thesidewallsofthetroughswillbequite flexiblewhenyou initially stand themup.Wesuggesthaving fiveor sixpeopleonhandtohelpwiththisjob.

The side andmiddlewalls butt into the endwalls.Standone sidewall andline it upwith the correspondingmark. Stand one endwall at a time and jointhemto theendsof thesidewall.Useat least three¼″×4″lagscrewsperbuttjoint.Firstdrillpilotholes,thencountersinktheheadsby¼″.Thetroughshould

nowlooklikeaverytall“C”.Standthemiddlewallandfastenittotheendwallsusing4″lagscrews.The

middlewallmustbe centeredonboth endwalls.Stand theother sidewall andfastentotheendwallsusing4″lagscrews.

Itislikelythattheframewillbefloppyuntilitisshimmedandlinedwiththepoly.Ifnecessary,usetemporary2×2bracingacrossthewidthofthetroughtokeepthesidewallsparallelduringthefinaladjustments.

Sheaththeinsideoftheendwallswith½″plywood,leavinga1″gapatthebottom.

Theframeofonetroughisnowassembled.Repeattheassemblyprocessfortheothertwotroughs.

FinalPlacementoftheTroughsUsespikesorshortpiecesofrebarandstringlinestolayouttheexactcornersofthetroughs.

44″ in from the eastgreenhouse endwall, use stakes tomount a string linenorth-southat14″high.Thisistheoutsideedgeoftheeastendofthetroughs.Use a permanentmarker to label the string at the center of themiddle troughusingtheplumbbobspreviouslyhungfromthecrossbraces,thenlabeltherestofthetroughcornerlocationsworkingyourwayoutwardinbothdirections.

Measure86′8″to thewest in3 locations: thesouthwestcornerof thesouthtrough, themiddle of the center trough and the northwest corner of the northtrough.Stretchanotherstringlinenorth-southat14″hightomarkouttheoutsideedgesof thewest endof the troughs.Mark the string line at the center of themiddletroughandthenthecornerlocationsofthetroughs,asbefore.

Useasledgehammerandastrikingblock(soyouarenotdirectlyhittingtheframes)totapthetroughsintoplace,liningthemupaccuratelywiththelabelsonthestringlines.

Once all corners of the troughs are in their final positions, use nine stringlinesstretchedeast-westfromcornertocornerasaguideandstraightenthesideandmiddlewallsbytappingthemintoplacewiththesledgehammerandstrikingblock.

Itislikelythatthetroughswillneedtobeshimmedwithwedgesorgravelasthecompactedgravelbaseisunlikelytobeperfectlylevel.Takeyourtimedoing

thisanduseasurveyor’sleveltoensurethatthetopsofthewallsareauniformheight.

TroughLinerInstallationWerecommendusing20milLDPEastroughliner.Thismaterialisoftencalled“geomembrane” and is used as a protective liner to prevent runoff in landfillsandwaste treatment facilities. Itmaybepossible toget a discountedprice foroffcutLDPE that is trimmed from a larger project.You can use up to 40milLDPE,whichiswhatwehaveinourgreenhouse,butitismuchmoredifficulttoworkwithduetoitsthickness,andincoldertemperatureswilllikelyneedtobewarmedbeforeinstallation.

LayingthesandbaseinnewlyconstructedtroughstoprotecttheLDPE.

Thelinermustbe14′wideand4′ longer thanyour troughlength(90′ long

for each86′ trough) to allowa littlewiggle room ifyoudon’t install the linerperfectlystraight.Thelinermustbewhiteonitsupperside(theothersidecanbeanycolorincludingwhite).

Rememberwhenorderingtoaddenoughforyoursump,andmoreifusingitfortheSeedlingTableorworkbench.

Beforeliningthetroughs,preparea1″compactedsandbaseinsidethemtopreventsharprocksfrompuncturingthelinerwhenfilledwithwater.Useafinebeddingormasonrysandthatisscreenedanddoesnotcontainanyrocks.

Spread the sand evenly inside the troughs and screed it level, using theplywood gap on the troughwalls as a guide.Compact the sand using a smallplate compactor or a hand tamper. Keep leveling and compacting until ascompactaspossible,levelandflushwiththebottomoftheplywood.

Youshouldreceivethelineronahollow-coreroll.Unrollitoverthelengthofatroughstartingatthewestend.Thebestmethodistohangtherollfromatractorbucketorforkliftanddragthelineroverthetrough.Leave2′overhangingbothendwalls.Ifyoupurchasedonerollwithenoughlinerforallthreetroughs,besuretocutthelengthpreciselysoyoudon’tleaveyourselfshort.

Markthecenterofbothendsofthelinerandmarkthecenterofthetroughonthe outside of the endwalls to assist in keeping the liner square on the frame.Push the linerdown into the troughalong theeastendwall,keeping thecentermarkslinedupandleaving6–12″ofoverhang.Bendthelineroverthetopedgeoftheeastendwallandtackwithafewstaplestoholditinplace.

IMPORTANT

Onlytackthelinertothetopedgeofthetroughwalls,neverbelowthewaterline.

IMPORTANT

Wheneveryouwalkonthelineratanypoint,youmustdosoincleansocksonly.Neverwalkonthelinerwithshoesoryouriskpuncturingit.

Workingfromtheeastend,pushthelinerdownalongtheinsideofeachsidewall and both sides of themiddlewalls.Do this bymaking numerous passes,always starting from the east (tacked) end and working towards the west(untacked)end.

RollingouttheLDPEforlinerinstallation.

Nearlycompletedtroughlinerinstallation.

IMPORTANT

Thebottomofthelineralongeachofthesidewallsandbothsidesofthemiddlewall,whereitmeetstheground,musthaveasmallcurvewitharadiusofapproximately2–3″.Donotpushthelinersquareintothecrease.Thiscurveisneededforthestructuralstabilityofthetroughoncetheweightofthewaterisexertingforce.Thecurvewilldistributetheweightofthewaterevenlybetweenthewallsandthegroundsothatthewallsareneitherpushedoutnorpulledin.Itisimportantthatthecurvesbeconsistentalongeachwallandinrelationtotheopposingwall.

Fold the linerateach insidecorneras ifyouarewrappingapresent.Someexperimentationwillberequiredtolearnthebesttechnique.Itisnecessarytocutslitsinthelinertofoldthecornersbutmakesurethatnocutislowerthanthetopofthetroughoncethelinerisfullyinstalled.Beconservativewithanycutsyou

make.Thebottomof the liner alongeachof theendwallsmustbepushed square

intothecreasewherethewallmeetstheground(nosmallcurvelikethesideandmiddlewalls).Thisisnecessaryfortheinstallationofthebulkheadfittings.

Troughconstructionasseenfromendwall.

Onceyou are satisfiedwith the position of the liner, including the cornersandcentermarkingsofbothendwalls,tackthelinertothetopoftheframeusingastaplegun.Startattheeastendwhereyouinitiallytackedandworkyourwayalong thesidewalls to thewestend.Donot tack themiddlewall.Remember:youmustnotwearshoeswhenwalkingontheLDPE.

Onceyouhavetackedbothsidewallsandthewestendwall,thelinerwillbeinitspermanentposition.Whenfillingthetroughswithwaterforthefirsttime,fillbothsidesofeachtroughatthesametimetopreventthelinerfromshifting.Unlessthecurvesinthelineratthebottomofthesidewallsareperfectlystraight

andparallel,whichisdifficulttoachieve,thewallsofthetroughsmaybowinoroutslightlyoncetheyarefullofwater.Thisshouldnotbeofconcern,unlessthebowissignificantenoughtopinchtheraftsortoextendtoofarintotheaisles.Ifthishappens,thebowcanbecorrectedbycementingaverticalsupportintothegroundlikeafencepost,andsecuringthesidewalltoit.

To permanently secure the liner and create a finished edge, fasten ¾″×2″woodtackstrips(ideallyredcedar)alongthetopsofthesideandendwallsusing1½″exterior screwsevery12″.Thescrewswillgo through the tackstrips, theLDPEandintothewallframes.Donotusetackstripsonthemiddlewall.

Usinganewbladeonautilityknife,trimtheexcesslineronallfoursides.Paintallexteriorsurfacesof the troughwallsusingawhite100%acrylic latexexterior paint. It ismandatory that the paint not contain anymold ormildewinhibitors(suchasMicroBan).Thisisthesamepaintyouwillbeusingtopainttherafts.

TroughPlumbingInstallationWaterwillflowinthenorthsideofeachtroughfromthewestend,takeaU-turnattheeastendandflowbackinthesouthsidetowardsthesump.

The 3″ bulkhead fittings used for the U-turns and drains can be quiteexpensiveandmaybedifficulttofind,butwestronglyrecommendthem.Theyprevent water retention andminimize the drain down effect that occurswhensmallerplumbingisused(seeDrainDownEffectinChapter2).Itispossibletouse2″plumbingforallthetroughconnections,butwedonotrecommendthis.Ifyou use smaller plumbing, youmust install a cistern that is connected to thesump to handle the drain down effect.We recommend installing a cistern nomatterwhat sizeplumbing isused,but it ismandatory if theU-turnanddrainfittings are smaller than 3″. The trough inlet fittings can be 2″ as this won’tincreasewaterretentioninthetroughs.

IMPORTANT

Whenusingaholesawtocutthroughthetroughwalls,alwaysdrillfromtheinsideoutasthiswillresultinacleaner,moreaccurateholeintheliner.

InletPlumbingAt the west end, install a 2″ bulkhead in the center of the north side of thetrough, as high as possible (just under the 2×3 top plate). From outside thetrough, mark the location of the bulkhead and drill a pilot hole through theplywoodand trough liner.Useahole sawof the correct size for thebulkheadfitting(usuallya3″holesawfora2″bulkheadbutmeasurebeforedrilling).

Placethebodyofthebulkheadthroughtheholewiththeflangeheadontheoutsideofthetrough.Bulkheadfittingsinthetroughsarealwaysinstalledwiththe flangeheadon theoutside tosavespace in thewalkways.Slide thegasketover the threadedbody inside the trough and thread the clamp ringonuntil itcompressesthegasketagainstthetroughliner.

Threada2″MNPTxslipadapter into theflangeheadand installa2″ballvalveascloseaspossible to thebulkheadontheoutside.Thevalvewillallowyoutoadjusttheflowtothetroughorshutoffthewatercompletely.

Troughdrainstandpipe.

TroughU-turnplumbing.

DrainPlumbingThetroughdrainstandpipescontroltheheightofthewaterinthetroughs.

Installa3″bulkheadforthestandpipedrainonthewestendofthesouthsideofthetroughaslowaspossible(justabovethe2×3bottomplate)withtheflangeheadon theoutside.Typically thiswill require a4″hole saw;measurebeforedrilling.Thread3″MNPTxslipadaptersintobothsidesofthebulkhead.

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Using two short pieces of 3″ PVC and one 90° elbow, make a standpipedrain inside the trough.Thepipe shouldextend to the topof the troughwalls.Youwillcutitdowntofinalheightlater.DonotgluethePVCpiecesandelbow.

Side-to-sidePlumbing(U-turn)Installtwo3″bulkheadfittingsontheeastendofthetroughs,oneoneachside,as low as possible above the 2×3 bottom plates. Connect the two bulkheadsusing3″pipeandtwoelbows,keepingthepipeascloseaspossibletothetroughendwall(tokeepthewalkwayasopenaspossible).ThisistheU-turnwherethewaterchangesdirectionandflowsbacktowardsthesump.

Repeattheplumbinginstallationfortheothertwotroughs.

EstimatedPartsListforTroughConstructionHereisanestimatedpartslistfortheconstructionofthree86′troughs:

1,800′of2×327sheetsof½″plywood270′of14′wideliner54¼″×4″lagscrews1½″screws3″screws½″staplesPlumbingfittingsPaint

Note that this is an estimate. As with all construction, do your owncalculationspriortoorderingandpurchaseextra.

RaftConstructionManufacturing rafts is a large repetitive job. For our design, you will beconstructingaminimumof258raftswith8,256totalholes.Treatingthejoblikeafactorylineassemblyandusinghigh-qualitytoolsishighlyadvised.

You must buy styrofoam that is extruded polystyrene. All other forms of

styrofoamwillbreakdownand/orleachintothewater.Youwillalmostcertainlyneedtospecialorderyourstyrofoam,whichwillcomein2′×8′sheetsthatare2″thick.Eachsheetwillbecutinhalf,creatingtwo2′×4′rafts.

Thefirststepistocreateatemplatefortheraftsfrom½″plywood.Riptheplywood to exactly 2′×4′.As described inChapter 2,we use a 32-hole layoutthatallowsforavarietyofplantspacings.Theholelayoutis4acrossthewidthand8alongthelengthofeachraftinacheckerboardpattern.Eachholeison6″centers,meaningthecenterofeachholewillbe6″fromthecentersofeachofitsfourneighbors.Thecentersoftheholesaroundtheoutsideare3″fromtheedgeoftheraft.

Afteryouhavemarkedout theholecenters,usea2″holesawtocompletethe template. Youwill be using 2″ net potswhich are designed to fit into 2″holes.Use a hole saw for accuracy and a corded electric drill to cut all holes(templateandstyrofoam).

Using the outside edge of the template for a guide, cut each piece ofstyrofoam in half, creating two 2′×4′ rafts. To make the cut, either saw thestyrofoamwithabreadknifeordeeplyscoreitwithautilityknifethensnapthepieceinhalf.Securelyclampthetemplate to thetopofaraftwithasacrificialsheetofplywoodbetweentheraftandtheworkbench.Drill32holesintotheraftthroughtheholesofthetemplate.

Youwillberemovingmorethan8,000piecesofstyrofoamwithaholesaw.Thiscanbetime-consumingandlaborious.Removingstyrofoamplugsfromtheholesawcanbeparticularlyfrustrating.Thebestmethodwedevelopedis this:screw two 3″ screws through a scrap of plywood, 1″ apart.With the exposedscrewsfacingupwards,screwtheplywoodsecurelyontoanysolidbase.Tocleartheplugfromtheholesaw,pushtheplugdownontothescrews,thentwistandlift at the same time.The styrofoamshould removecleanlyand remainon thescrewsfordisposal.

Repeattheprocessuntilyouhavecreatedallofyourrafts.While 258 rafts is the minimum required to fill the troughs, we suggest

creatingatleast10additionalspareswithholescutoutandkeepinganadditional50blankrafts (withoutholes) foruseasplaceholderswhileharvested raftsarewashedandreplanted.

PaintingtheRaftsTheraftsmustbepaintedwhiteonallareasthatwillbeexposedtodirectlight.Thismeansoneface(thetopsurface),allfouredgesandtheinsideofeachoftheholes.Donotpainttheundersideoftherafts.Usethesame100%acrylicpaint(with no mold or mildew protection) that you used to paint the troughs. A“brilliantwhite” base is ideal.Thepaintmust be a gloss or semi-gloss as thiswill be easier to cleanandwill standup to regular cleaningbetter than flat ormatte.

Thestyrofoamwillhaveprintingononeside;makethisthetopsurface.Usearollertopaintthetopsurfaceandtheedges.Topainttheinsidesoftheholes,dip the end of a paint roller in the paint and push it through each hole.Wesuggestusing tworollers:onefor the topandedges,onefor theholes.Paintaminimumoftwocoats.

Painted rafts need to cure for at least oneweekprior tobeingput into thesystem.Iftheweatheriscompliant(notraining),theidealplacetocuretheraftsisoutsideunder the sun.After aminimumofoneweek,wash the raftswithamilddetergent.Don’tscrubhard.

If treated with care and not scrubbed aggressively when cleaning, raftsshouldlastmanyyears,thoughtheywillneedtoberepaintedeveryfewyearsasdictated by the degradation of the paint due to friction, scrubbing and UVexposure.

As the raftsareunidirectional (thepaintedsurfacemustalwaysbeup), theundersideof theraftswillbecomecoatedwithabiofilmofbeneficialbacteria.Neverscruborwash theundersideofyour rafts.The topwillbecleanedaftereachharvest(seeChapter9).Thebottommustbeleftaloneor,ifneeded,gentlysprayedcleanwithahose.

When rafts arenot in the troughs, alwaysprotect theunpainted sides fromsunlight as the UV radiation will quickly degrade them. Degradation will benoticeableasafinedustwhentheraftiswiped.Thoughthedustisnon-toxic,itshouldbekeptoutofthesystem.

SourceWaterInstallationTheinstallationofsourcewaterwillvaryfromsite tosite. It is likely thatyou

willneedtousepex,notsimplegardenhose.Youmaybeabletorunthewaterlineinthesametrenchastheelectricalcable.Followcode.

Sourcewater is requiredata fillingstationover thesump,at thesink,atahose faucet outside for washing rafts and filters and to connect the washingmachine.Thefillingstationshouldhaveatleasttwovalvedlines:onetotopupthe sump on a regular basis via a timer and one to fill bins for jobs such aswashingplants.Werecommendatallpre-rinsefaucetoverthesink.

AquacultureSubsystemInstallationThis section covers installation of the fish tanks, TankManifold,Radial FlowSeparator(RFS),CombinationFilterBox(CFB),pumps,UVsterilizersandtheplumbingconnectionsbetweenthem.

Muchoftheplumbingofyoursystem,thearteriesofthefarm,willbehiddenunderground.Thepipeswillallbeneargroundlevel,usuallyonlyafewinchesbelowthesurface.Thepipesdonotneedtobeslopeddownhillinthedirectionof flow.Level is satisfactory.Bemindful to avoid airlockswhich can happenwhenpipesarearrangedinan“n”or“u”configuration.

Theplumbinginstallation,bothunder-andaboveground,willbeoneofifnotthemostcomplicatedandpreciseconstruction jobs. It iscomplexandmustbedone with a high degree of accuracy in three dimensions. We stronglyrecommendyouhireaprofessionalplumber.

IMPORTANT

UseonlyPVCgluethatissafefordrinkingwatersystemsanduseitsparinglytoavoidexcessgluesqueezingoutofthejoints.Dryfiteachsectionofplumbingpriortogluing.

All pipe in the facility is Schedule 40 PVC.Unlesswe specify otherwise,whenwerefertopipe,wearereferringtoSchedule40PVC.

1.2.3.4.5.6.7.8.9.10.11.12.13.

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Wherever possible, use sweeps for 90° bends rather than elbows. Sweepshaveapproximately30%lessfrictionlosscomparedwithelbows.

Followthisorderforconstructionandinstallation:

LayoutRoughintheMainWastePipe(MWP)InstallthefishtanksBuildandinstalltheStandpipeAssemblies(SPAs)InstalltheRadialFlowSeparator(RFS)InstalltheTankManifoldConnecttheSPAstoTankManifoldtoRFSBuildandinstalltheCombinationFilterBox(CFB)ConnecttheCFBtotroughsInstalltheUVunitsConnectUVunitstofishtanksInstallthepumpsConnectthepumpstotheUVunits

LayoutBefore breaking ground to lay pipes, you must first lay out all the majorcomponents:thefourfishtanks,RFS,TankManifoldandCFB.Wesuggestyoualso lay out the Seedling Table andworkbench.Use non-toxicmarking spraypaint.Accuracyisimportant,nottotheinchbutwithinafewinchesatmostinall directions for each object. For round objects like the fish tanks, createaccuratecirclesbydrivingastakeinthecenteroftheobjectlocationandusingamarkedstringoftherequiredradiustocreatethecircumference.

Youmayneedtoplayaroundwiththelayoutabit,remarkingthelocationsofitems.

Thebasicrequirementsofthelayoutforbothsystemsare:Sufficient space to move and work around the outside of all four tanks(shouldbe3′minimumatallpoints)AccesstotheRFSandSPAsfromthesouthThe spacebetweenTanks2&3will be alignedwith the centerlineof thegreenhouseandthemiddlewallofthecentertrough

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TheeasternedgesofTanks2&3shouldbe3′fromthewesternedgesofthetroughsLeavea1′gapbetweenTanks1&2and2&3attheirclosestpoints

Walkaroundthelayoutyouhavecreated.Imaginetheheightoftheobjectsandconfirmthatyouarehappywithbothwalkingandworkingspace.

Onceyouaresatisfiedwiththespraypaint layout,markthelocationofthefourStandpipeAssemblies.TheSPAsforTanks1,2&3willconnect toboththeTankManifold and theMainWaste Pipe (MWP).The SPA for the PurgeTankwillconnectonlytotheMWPunlessitisbeingusedasahatcherytankorfora4thcohort,inwhichcaseitwillalsoconnecttotheTankManifold.

InstallingtheMainWastePipeThe first pipe to lay is theMWP from the RFS towards the west end of thegreenhouse.TheMWP is a4″pipe that carries effluent from theRFSand thefourfishtankstotheWasteTanksoutsidethegreenhouseonthewesternside.

MainWastePipeplumbing.

DigatrenchfromtheWasteTankthatrunsundertheslidingdoorsandendsattherough-inpointbetweenthePurgeTank,RFSandTank1.Thetopofthepipeatthispointshouldbe6–12″belowground.

InstalltheprimaryWasteTankinitsexcavatedsiteattheappropriateheight.Glue the pipe sections together, lay them in the trench and install a

temporarycaptopreventdirtfromenteringthepipe.Backfillmostofthetrench,leavingthecappedendexposed.YouwilllaterconnectthistotheRFSandthefourSPAs.

InstallingtheFishTanks

Thefirststepistobuildasupportringonthegroundforeachtank.Theblocksyouusemustbecapableofformingacircle.For thisweusedandrecommendAllanBlockretainingwallblocksastheyhavewingsthatcanbeeasilyremoved,convertingeachblockintoawedgeshapewhichisidealforformingcircles.Thesupport ring will be filled with a bed of sand, and the tanks will sitapproximately halfway onto the blocks. The tanks will not sit directly on theblocks,theywillonlycontactsand.

AtthelocationofthefourSPAs,leaveagapinthesupportringwideenoughfor each tank’sbottomdrainpipe topass through (approximately6″).Startingwiththegap,workyourwayaroundthecircumferenceofeachring,settingtheblocksintoplace.Makeabedofsandforeachblockasyougo.Useahammerandwoodenstrikingblock to firmlyseteachblock into the sand.Usea stringlinefromapeginthecenterofthecircletoensureit isperfectlyround.Useasurveyor’sleveltoensurethateachblockisinstalledatthesameheight.Useabuilder’sleveltoconfirmtheheight.

IMPORTANT

Itiscriticalthatthetopedgesofthetanksareallthesameheightinrelationtooneanother.

Tanks2&3onbaseswithroughed-inplumbingandRFS.

Eachring(and thehollowcoreofeachblock) is filledabovethe lipof theblocks with fine bedding sand. It is very important that there be no rocks orsharpobjects in thesand.Compact thesandwithahand tamperorsmallplatecompactor.

IMPORTANT

Itiscrucialthatthesandinstallationbesufficientsothatthetanksonlycontactsand.Expectsomesettlingwhenplacingthetanksduetothepressureoftonsofwater.

Thebottomdrainislocatedatthebottomoftheeachtankinthecenter.Digoutadepression in themiddleof the ringappropriate to the tankdesignandatrench for the drain pipe from the center of the circle through the gap in theblocks.Many tanks will have a gentle slope in the bottom. Try tomatch theprofile of the base of the tank with the sand. Lightly wet the sand prior todiggingtocreatemorepreciseshapes.

Tanks will typically be shipped upside down.While upside down, glue apipeintothedrainofthetank.Thepipewillnotbecuttofinallengthatthistimeand should simply extend past the blocks by a foot or two. This will laterconnecttoateeatthebottomofitsSPA.

Oncetheglueisset,carefullyturnthetankoverwithateamofatleastfourpeopleandgentlysetitintoplace.Checkthatitislevelusingastraight2×4andabuilder’slevel.Thetankmayneedtobeshiftedaroundslightlytosettleitintoalevelposition.

Repeattheprocessfortheotherthreetanks.Useasurveyor’sleveltoensurethetopsofalltanksarelevelwitheachother.

BuildingtheStandpipeAssemblies(SPAs)The SPAs for Tanks 1, 2 & 3 each have one inlet (from the tank) and twooutlets:totheTankManifoldandtotheMWP.TheSPAforthePurgeTankisthesameconstruction,onlyasmallerdiameter,andtheoutletisnotconnectedtotheTankManifoldunlessitisgoingtobeusedasanadditionalculturetank.

TheonlydifferencebetweentheSPAsforTanks1,2&3isthattheSPAforTank3hasanelbowatthebottomasitisthebeginningoftheMWP,whereastheSPAsforTanks1&2(and thePurgeTank)have teeswhere theyconnectinlinetotheMWP.

Eachof theSPAsforTanks1,2&3willhavea4″outerpipe,a2″ innerpipe,anda4″×2″bushingatthebottom.The2″piperunsinsidethe4″pipeandplugs into thebushing toblock the loweroutlet to theMWP.Lifting the innerpipewillalloweffluenttoflushintotheMWPandouttotheWasteTanks.The2″pipeextendsapproximately12″past the topof the4″pipeso that itcanbeeasilygripped for lifting.The2″pipemustbecapped topreventodor leakagefromtheWasteTanks.

TheSPAforthePurgeTankisbuiltinthesamemannerexceptthattheouter

pipeandbothteesare3″,theinnerpipeis1½″,andthebushingis3″×1½″.TheconstructionoftheSPAsisstraightforward.Simplyfollowthediagram.

Startbymodifyinga4″×2″bushingbycuttingoffthewrenchingfinstoallowittofitbackwardsintothe4″tee.Thefinsmustbecleanlyremovedwithouttakingofftoomuchmaterial.Theremustbenogapsbetweenthebushingandthetee.Useanoscillatingtoolorfinetoothhacksawtoremovethefins,thensandpapertoroundoffthebumpsuntilthebushingfitssnugglyintothetee.

StandpipeAssemblies.NotethateachSPAsetsitstankwaterheight.

Gluethebushinginreverseexactlyhalfwayintothe4″tee.TheotherhalfofthebushingwillbeconnectedtotheMWP.

Atthistime,installa4′lengthof4″pipeinthetopofthelowertee.Youwillinstalltheupperteethatdeterminesthewaterheightlater.

IMPORTANT

Theupperteewillnotbegluedsothatyoucanswivelitorcorrectitsheightasnecessary.

Connect eachSPA to its tankdrainas shown in thediagram. Ifnecessary,useacouplingandalengthofpipetoextendthetankdrainpipetothelocationoftheSPA.

ConnectthePurgeTankSPAtotheMWPviaateeintheMWP,thenextendtheMWPtoconnecttotheSPAsofTanks1,2&3inthatorder.

RoughintheplumbingfromtheRFStotheMWP.TheconnectionpointwillbebetweenthePurgeTankandTank1.UsepipesizedfortheoutletoftheRFS.Capthepipetopreventdebrisfromgettingin.

TheheightoftheupperteeineachSPAdeterminestheheightofthewaterinthecorrespondingtank.FinalizetheheightoftheSPAsbycuttingthevertical4″pipeandfittingtheupperteeoneach.Thetopoftheoutletoftheteemustbe3″belowthelipofeachtank.Itisvitalthatthisbeexactasthiswilldeterminetheheightofthewaterinthetank.

InstallingtheRadialFlowSeparatorTheRFShas one inlet that comes from theTankManifold and twooutlets: aloweroutlet that connects to theMWP to removeeffluent andanupperoutletthatconnectstotheCFB.

Once in its finalposition, the topof theRFSmustbe4–6″ lower than thebottom of the outlet pipes on the 4″ upper tee of the SPAs. The RFS maythereforeneedtobepartiallyburied.Useasurveyor’sleveltosettheRFSatthecorrect height, making sure it is perfectly level and that the upper outlet ispointed in the direction of theCFB.Use a compacted gravel or cement blockbasetopreventtheRFSfromsettlingortipping.ConnecttheloweroutletoftheRFStotheMWPandbackfillaroundthebaseoftheRFS.

Once the RFS and all SPAs have been set in place and connected to theMWP,theMWPandthebasesoftheSPAscanbebackfilled.

InstallingtheTankManifoldTheTankManifoldmustbeafood-gradeplasticbarrelorcontainer,ideallywithalid.A50-gallonpolyethylenebarrelworkswellasithassturdywallsthatcanbeeasilycutordrilledandawidecircumferencewhichishelpfulforattachingfittings.

The topof theTankManifold isat least thesameheightas the topsof thefish tanks, and the bottom is 6–8″ lower than the bottom of the RFS inlet,leavingjustenoughroomfora4″bulkhead.IfthebottomoftheTankManifoldis lower than this, large settleable solids from the fish tanks will collect hereinstead of being carried into theRFS, and theTankManifoldwill need to becleanedoutregularly.Ifneeded,buildasmallplatformsimilartothetankringstoelevatetheTankManifoldtothecorrectheight.Ifthetopofthemanifoldissignificantlyhigherthanthetanks,itcanbecutdowntoafewinchesabovebutnolowerthanthetopofthefishtanks.

Once theTankManifoldhasbeen set inplaceat the correctheight, installthree4″UnisealsfacingtowardstheSPAsofTanks1,2&3atthesameheightas the outlets of the upper tees in the SPAs. Connect the SPAs to the TankManifoldwithlengthsof4″pipe.Use45°or22.5°fittingsasneeded.

ConnectingtheTankManifoldtotheRadialFlowSeparatorTheinletontheRFSwillconnecttotheoutletontheTankManifold.Tocreatetheoutleton theTankManifold, installaUnisealon themanifoldat thesameheightattheinletontheRFS.TheUnisealandconnectionpipesizewillbethesameastheinletontheRFS.

ConstructingtheCombinationFilterBox(CFB)TheCFB is a custom filtration component thatmust bewell-built precisely tothefollowingspecifications.

We recommend building the CFB from ¾″ marine-grade plywood,waterproofedwithepoxyresin. Ifdifferentmaterialsareused, followthesamedesignguidelinesandusetheexactdimensionsasoutlined.

Usethedimensionsshowntocutthebottom,lid,sidesandendsoftheboxfromtwosheetsofplywood.Theinsidedimensionsofthefinishedboxare58.5″longby24″wideby20.5″tall.Theendsaresandwichedbetweenthesides.

Glue and screw the sides and ends together using 2″ exterior screws andepoxy resin, then glue and screw the bottom onto the box. Make sure it isalignedsquarely.Ensurethatalljointsaretightwithnogaps.Makesuretoapplyenough epoxy resin that it squeezes out of the joints, then wipe smooth theexcess.

Tomaketheribs,cut24stripsof¾″plywoodthatare1″by19¾″.Installtheribs according to the diagram,with 9 pairs of ribs at the upstream side (inletfromRFS)and3pairsat thedownstreamside(outlet to troughs).Theribsare1½″apart tohouse the filter screens.The space inbetween the twogroupsofribsisfortheMovingBedBio-Reactor(MBBR).Therewillbe3½″betweentheouterribsandtheendsofthebox.

Notethatribsarerequiredonboth(opposite)sides.ThediagramshowsribsonlyononesideoftheCFBinordertoshowdimensionsclearly.

The ribs are flush against thebottomof theboxwith a¾″gap at the top.Drillpilotholesthenfastentheribstotheinsideoftheboxusing1¼″exteriorscrews.Screwfromtheoutsideoftheboxintotheedgeofeachstrip.Theribsstand 1″ in from the walls of the box. Ensure the strips are snug against theinside.

CFBconstructionblowup.Notethattheribs,shownhereonlyononeside,areinstalledonbothsides.

Thelidisfittedwithfourstripsof¾″plywoodontheundersidetoholditinplace.Theouteredgesofthestripsare⅞″infromtheedgeofthelid.Wheninplace,thestripsfitsnuglyinsidethewallsofthebox,ontopoftheribs,andthelid’sweightkeepsthefilterscreenstightagainstthebottomofthebox.

Cut twoholes forbulkhead fittings,oneateachendof thebox.Match theinlet bulkhead in the north end to the RFS outlet and cut as high as possiblewithout interferingwith the lid. The outlet bulkhead on the south end (to thetroughs)is4″,andthetopoftheholeis6″belowthetopoftheboxwall.

Cutaholeforthe1″bulkheadforaerationintheeastsideinthecenteroftheareafortheMBBR.Thetopofthe1″bulkheadis1″belowthetopoftheside.

BesidetheinletfromtheRFSintheupstream(north)end,cutaholeforthe

1½″bulkheadforthebypassfromthepumps.Cuteachholewithaholesawthatisjustlargeenoughforthebulkheadsto

fitsnuglythrough.Testfitthebulkheadsbutdonotinstallthemnow.The CFB is now assembled, time to reinforce and waterproof it with

fiberglassandepoxyresin.SeeIMPORTANTnote(page80)onepoxyandfishsafety.Reinforce the four vertical corners of the box by filleting the seams with

woodand/orabeadof thickenedepoxyresin.A“fillet”covesandstrengthenstheinsidecornerswheretwoplywoodpanelsmeet.Beforethefilletfullycures,coverthecornerwitha6″widestripoffiberglasscloth.Immediatelysaturatethecloth with resin and push out all the air bubbles with a plastic scraper orfiberglass roller.Allowtheresin tocureuntil it is firmbutstill softenough toindentwithathumbnail.

Beforethefilletisfullycured(typically1–3hours),waterprooftheboxwithresin.Saturatetheentireinsidewiththreecoats.Successivecoatscanbeaddedonce the previous coat has “kicked off,” or gelled over, but before it is fullycured.Iftheepoxybecomestoohardtoindentwithathumbnailbetweencoats,waituntilitisfullycuredbeforerecoating.

Be sure to fully saturate all seams, corners and around the holes and topedges of the box. Be generous with the resin — the plywood will soak upconsiderablequantities,particularlytheedges.

FiberglasscornerfilletintheCFB.

Saturate thesidesandedgesof the lidandthelidstripswith threecoatsofresin.The lidwill inevitably become valuable bench space, so protect itwell.Saturatetheoutsideoftheboxwithtwocoatsofresin.

Allowtheresintocureforatleast24hours.Aftercuring, therewillbeawaxy“amineblush” lefton thesurfaceof the

epoxy.This residue iswater-solubleandmustbe thoroughlywashedoffusingonlywarmwaterandasoftcloth.Donotuseanysolventsordetergents.

Use120gritpapertolightlysandtheglossoff theepoxyontheoutsideofthebox(allfoursidesandlid),thenpaintitusingthesamewhitepaintusedontherafts.Donotpainttheinsideoftheboxorthebottomofthelid.

Attachthebulkheadfittingstothebox,clampingthegasketstightlyinside.

CFBtopview.

InstallingtheMovingBedBio-Reactor(MBBR)Ontheinsideofthe1″bulkhead,assembletheaerationsystemfortheMBBR.This consistsof a checkvalve, a tee, two6″ armswith caps, six¼″MNPTxbarbfittings,¼″airtubingandsixairstones.

Cuttwo6″lengthsofpipetocreateamanifoldwithtwoarms.Ineacharm,drillthreeholesthatareslightlysmallerthanthethreadedendofthe¼″MNPTxbarbfittings.Usea¼″threadtaptocutthreadsintotheholesandscrewinthebarbsusingTeflontape.Capthearms.

InsidetheCFB,installalow-pressureswingcheckvalveonthe1″bulkheadtopreventwater frombackflowingdown theairpipe. Install a1″ teeonto thecheckvalveandgluethetwoarmstothetee.Cutsixlengthsof¼″airtubingtoequally space the air stones around the bottom of theMBBR. Attach the airstonestothebarbfittingsinthearms.

IMPORTANT

Installthe¼″MNPTxbarbfittingspriortogluingthearmsintoplace.

InstallingtheFilterScreensEachscreenis24″wideby19.75″talland1.5″thick.WeuseandrecommendMatalafiltermediawhichcomesin48″by39″sheets,1.5″thick.Eachsheetiscutdown themiddlebothways to create fourpieces that fit perfectly into theCFB.

Matala filters are available in four grades, identified by different colors.Starting from the inlet side, use four black (low-density) screens, followed bythree green (mid-density) screens, then one blue (high-density) screen.On theothersideoftheMBBR,installonegreenthenoneblue.TheselasttwoscreensactasacontainmentbarrierfortheMBBRmedia,preventingitfromflowingoutofthebox.

TheCFBisspecificallysizedtohouseMatalafilterswithnoexcess.Ifyouchoosetouseanotherbrandorstyleofscreeninyourbox,youmayreconfigurethe dimensions of the box. If you do so, note that the total volumemust notdecreaseandtheoverallshapeandlayoutshouldbeascloseaspossibletoourdesign.

Finally, fill the MBBR with the filter media. We use and recommendSweetwaterSWXbio-mediawhichissoldbythecubicfoot.Youwillneedfourcubicfeetwhichwillprovideabout93m2(1000ft2)ofBSA.

InstallingtheCombinationFilterBoxPositiontheCFBascloseaspossibletotheoutletoftheRFS,allowingroomforplumbing connections and to comfortably walk and work around it. Alsoconsiderthatin-groundplumbingwillbelaidcloseby.

TheheightoftheCFBisdeterminedbytheheightoftheoutletpipeonthe

RFS.TypicallytheRFSoutletwillbepointingdown,soyouwillneedtofitanelbowontheoutletandsettheCFBhighenoughthatitsinletlinesupwiththeelbow.

Markthefinalplacementandbuildabaseforitoutofcementblocks,usingasurveyor’s level to determine the correct height.Double-check that the box isperfectly level in all directions and is at the correct height before makingplumbingconnections.

The upper outlet on the RFS connects to the inlet on the CFB.You havealready cut the CFB inlet tomatch the size of the RFS outlet and installed abulkhead.Aswithallplumbinginyoursystem,useasfewbendsaspossibleandusesweepsinsteadofelbowswherepossible.

Filterscreen(right)andMBBRmedia(left)intheCFB.

InstallingtheUndergroundPlumbing(TroughSide)TheCFBwillconnectundergroundtothetroughs.Thepipewillrunbetweenthesump andTank 3. For a tower system, theCFBwill connect to the northeastcornerofthesump.

Digatrenchthatis6″deepand12″widealongthewestendofthetroughsandbetweenthesouthtroughandthesump.Itshouldbeascloseaspossibletothetroughendwallsandrunfromthesouthendofthesouthtroughuntilitisinlinewith theaerator.The trenchwill contain the troughdrainpipe, the troughinletpipeandtheairdistributionpipe.

Dig a second trench between the sump andTank 3 that is 6″ deep and 6″wide and that runs from the outlet of the CFB east to intersect with the firsttrench.Thiswillcontainthe4″piperunningfromtheCFBtothetroughinlets.

Laythepipesinthetrench.The4″troughdrainpipeisclosesttothetroughs(farthesteastinthegreenhouse).The4″inletpipeliesbesideittothewest.The2″airpipesitsinthegroovebetweenthetwo4″pipes.

Waterandaerationplumbingschematic.NotethatwaterplumbingfromtankstoTankManifoldtoRFSto

CFBisnotshown.

Laythe4″troughdrainpipefromtheoutletofthenorthtroughtothecenterofthesump.Thepipemustbeattherightheighttopassthroughthesumpcollar.Drillaholeinthecollar,aslowaspossibleandjustwideenoughforthepipetofit tightly.Before inserting the pipe, seal the inside of the hole frommoisturewithepoxyresin.Insidethesump,placea4″elbowontheendofthepipe.Donotgluetheelbow.

Connectthetroughdrainpipetotheoutletsonthesouthsideofeachtrough.Cut thepipebelow the troughoutlets and install a4″×3″ tee.Using two shortsectionsof3″pipeandoneelbow,connecteachtroughoutlettothetroughdrainpipe.Keepeverythingasclosetothetroughsaspossible.

Using4″×2″ tees,connect the4″ trough inletpipe to thevalvespreviouslyinstalled on the north side of each trough in the same manner as the drains.Where the inlet pipe intersects the trench from the CFB, use one sweep tocontinue the inlet pipe towards the CFB. As close to the CFB as possible,connecttheundergroundpipetotheoutletoftheCFBusingsweeps.

InstallingtheAerationPipeThe2″undergroundairdistributionpiperunsfromtheaerationblowers(locatedundertheworkbench)alongthewestendofthetroughswithonebranchtothenortheastcornerofthesumpandanotherbranchtotheCFB.

Extend the existing trough drain/inlet trench past the north trough to theaerationblowers.Lay2″pipeinthetrench,runningtothenortheastcornerofthesump,inthegroovebetween(ontopof)thetwo4″pipes.Temporarilycaptheendneartheaeratortopreventdirtfromentering(donotglue).

At the sump end, use one elbow to run the pipe from the south troughendwall to the sump.Drill a hole in the east side of the sumpcollar, near thecorner,sothatthepipewillrunalongtheinsideofthenorthcollar.Sealtheholewithepoxyresinbeforefittingthepipe.Oncethepipeisthroughthecollar,gluea2″ballvalveontotheend.Later,youwillconstructamanifoldtodistributeairto thediffusers in thesump.Seediagramshowing thesump topviewonpage79.

Cuttheairpipeatthecenterofthemiddlewallofeachtroughandinstalla2″×1″ tee.Placea1″ riserpipe ineach teeso that it risesa few incheshigherthantheendwall,directlyinlinewiththecenterofthemiddlewall.Temporarilycaptherisers(donotglue).

CuttheairpipewhereitintersectsthetrenchtotheCFB,besidethe4″inletpipe.Inserta2″teeandruntheairpipetojustbelowthe1″bulkheadontheeastsideoftheCFB.Usea2″elbow,a2″×1″bushing,1″pipeandanother1″elbowtoconnecttheairpipetothe1″bulkheadontheCFB.

Onceallpipeisgluedandinstalled,backfillthetrenchesthenaddalayerofcrushedgraveltomakeaflatsurface.

AerationBlowersInstallation

IMPORTANT

Topreventthepossibilityofwatersiphoningintotheaerators,theoutletpipesmustbeinstalledhigherthanthesurfacelevelofthewaterinthetroughs.Youwillneedtobuildaplatformfortheaeratorsundertheworkbench.

As discussed in Chapter 2, our design calls for installation of two identicalaeratorsforredundancy.Theaeratorswillbelocatedundertheworkbench,nextto the north wall of the greenhouse. Follow the manufacturer’s instructionsclosely.

Aerationblowerinsound-dampeningboxwithfrontofboxremoved.

Installtheaeratorsinparallel,withtheiroutletsconnectingtoa2″teeontheend of the underground distribution pipe. Install a ball valve on each aeratorbefore themanifold so that you can easily switch between the two.Only oneaeratorwillbeactiveatanytime.Optionally,installanairpressureswitchandarelayswitchbetweenthetwoaeratorssothatifonefails,theotherautomaticallyturns on. If installing a relay switch, youmust use swing check valves ratherthanballvalves.

If you only install one aerator (which we do not recommend), you mustconnecttheaeratortothemonitoringsystemtobothinformyouofaunitfailure

andautomaticallyactivatethebackupoxygensystem.SeeChapter5fordetailsonbackupoxygenandmonitoringsystem.

An aerator can be quite loud, and it will be operating 24/7 in yourgreenhouse. A simple sound-dampening box constructed of lumber andplywood,linedwithrigidstyrofoamand/orcarpetwillgreatlyreducethenoise.Itisvital,ifbuildingaboxthatitNOTbesealed.Airmustbeallowedtofreelyenter the box both for supply to the unit and for the unit to remain cool.Ourrecommendedmethodistoleavea2″openingacrossthewidthoftheboxatthetopofthefrontandback.

Ifyouraeratorscomewithalengthofrubberpipetoconnecttheoutletoftheaerator to the air distribution line, use it. This rubber pipe is designed fordissipatinganyheatthatmaybuildupfromthecompressionofairthroughtheblower. In extreme cases, if the air pressure in the pipe is high enough, thetemperaturecangethotenoughtomeltPVC.Oursystemisdesignedtooperateatlessthan1psi,soheatshouldnotbeanissue.

Likeawaterpump,anaeratorisdescribedbyaperformancecurvegraphthatshowstheflowrate,measuredincubicfeetperminute(CFM),atagivendepthofwater.Unlikeawaterpump, the friction lossesassociatedwithpumpingairare miniscule, and total head does not need to be calculated. The onlysubstantive restriction to flow is thedepthofwateratwhich theair leaves thediffuser.

The sizeof the aerator is determinedby thenumber of air diffusers in thesystemmultiplied by themanufacturer’s suggested flow rate.We recommendusingoneSweetwaterAS5airstoneundereveryraft.TheAS5stonesare3″×1″and have a suggested flow rate of 0.3 CFM each. For 86′ troughs, you willrequire258airstones,whichequal77.4CFM(258×0.3).

For the sump and the MBBR, we recommend using sixteen SweetwaterAS15airstones(teninthesump,sixintheMBBR),withasuggestedflowrateof0.5CFMeachforatotalof8CFM(16×0.5).

The total airflow required for86′ troughs is therefore85.4CFM@10″ofwater. We recommend the Sweetwater SST30 regenerative blower (orcomparable). The SST30 is slightly bigger than is required, but it is better tooversizetheaerator.Itisnotpossibletoover-oxygenatethesystem,andunder-oxygenatingisdetrimentaltoalllivingthingsandmayleadtosystemcrashes.

IMPORTANT

Thegoalistofullysaturatethewaterwithoxygenbythetimeitexitsthesumpsothatthefishreceiveasmuchoxygenasthewatercanhold.

Oncetheaeratorshavebeeninstalledundertheworkbench,connectthemtotheundergroundairdistributionpipe.

Installadedicatedpowercircuit for theaerators(seeElectrical Installation,thischapter).

AirStoneInstallation

IMPORTANT

Drillandinstallthe¼″MNPTxbarbfittingsinthe1″airpipepriortoinstallationoftheairpipesonthemiddlewall(seebelowforinstructions).

Air is delivered to the stones in each troughby a 1″ distributionpipe runningalongthetopofeachmiddlewall.Airstonesarelocatedundereveryraft(every2′)andconnectedtothedistributionpipeviaa¼″90°MNPTxbarbfittingand3′of¼″vinylairtubing.Thefittingsareelbowsandhaveathreadedendandabarbed end. The threaded end connects into the 1″ pipes, and the barbed endconnectstothe¼″airtube.

Each 86′ long trough requires 86′ of 1″ pvc pipe, 86 Sweetwater AS5 airdiffusers(43perside),86MNPTxbarbfittings,and258′of¼″vinyltubing.

¼″90°MNPTxbarbfittingforaeration.

Layoutthe1″pipeandmarkthelocationsofthediffuserconnections.Maketwomarks1′fromtheendofthetroughandthentwomarksevery2′.Thetwomarksareonopposite sidesof thepipe (180° fromeachother, facing towardstherafts).

To install the fittings, drill ³⁄₁₆″ holes in the 1″ pipe at each mark. Drillslowly and without applying too much pressure, or you will crack the PVC.CrackedorotherwiseruinedPVCmustnotbeused.Thespoiledsectionscanbecutoutandcoupledbacktogetherifdesired.Expecttospoilsomepipeasthisisa finicky job, which is why we recommend installing the fittings prior toinstallingthepipesonthemiddlewalls.

Onceyouhavedrilledtheholes,usea¼″threadtaptocreatethreadsontheinsideof theholes.ThreadafittingintoeachholeusingTeflontape tokeepit

airtight.Completeallfittinginstallations,thengluethedistributionpipesonthemiddlewallsofeachtroughpair.

At each trough, remove the temporary cap on the 1″ riser. Connect a 1″elbow to the top of the riser and lay 1″ pipe with fittings installed along thelengthofthetopofthemiddlewall.Captheairpipesattheeasternendsofthetroughs.Usepipestrapsevery10′tosecuretheairpipetothetopofthemiddlewalls. It is acceptable to penetrate the top of theLDPEonly for this purpose.Remember:donotwearshoesinthetroughs.

Oncetheairpipeshavebeeninstalled,connect3′of¼″vinylair tubingtothebarbedendofeachfitting.ConnectanairstonetotheotherendoftubeandfittwoflexibleO-ringsovereachairstone.TheO-ringswillactasbumperstopreventtheroughstonesfromrubbingonthetroughliner.

In thesump,aerationisprovidedbya2″pipethatrunsalongtheinsideofthenorthcollar,enteringfromtheeast.Installeleven¼″MNPTxbarbfittings:ten for air stones and one for an air pressure switch which connects to themonitoringsystem.ConnectairtubingtoeachfittingandairstoneswithO-ringsontenofthem.Runtheairtubingforthemonitoringsystemtothewestendofthesump,whereitwilllaterbeconnectedtoanairpressureswitch.

PumpSidePlumbingInstallationInstallingtheUVSterilizersThe first step is to determine the units you will be installing using theinformationinChapter2.Thelayoutoftheunitswilldependonthenumberyouwillbeinstalling.Therecommendedunits(SmartUVHigh-OutputE150S)are5′longeach.Allunitsmustrunparalleltoeachotheronahorizontalplaneandshouldbeaslowaspossibletothegroundtominimizesystemhead.

IMPORTANT

Ifforanyreasonthemainpumpsneedtobetemporarilyshutdown,alsoshutdownthepowertotheUVunits.LeavingthebulbspoweredwithnowaterflowwillrapidlyincreasethewatertemperatureintheUVunitswhichcandegradethelifeofthebulb.

The units are located between the sump and the southwest corner of thegreenhouse,runningeast-west.Support thesterilizersbybuildingarectangularframeoutof2×12 lumberandcuttingsemicircles in theeastandwestends toseat the round bodies of the units. The frame must be tall enough toaccommodatetheconnectionsfromthepumpsandthereplacementofthebulbs.

Usingajigsaw,cutsemicirclesthesamediameterastheunitbodiessotheywill fit snugly. The sterilizersmust be evenly spaced and at the same height.Securetheunitstotheframewithgalvanizedorstainlesssteelstrapping.

TheUVbulbswillbealmostthesamelengthasthehousingandarereplacedbyslidinginandoutofoneendofthehousing.Theunitsmustbehighenoughandinstalledinthecorrectorientationtoallowenoughroomtochangethebulbsabovethelidofthesump.

DuetothedesignoftheUVunits,theyarepronetotrappingbubblesofairin theexposurechamberbetween thequartz sleeveand the sterilizerbody.Topreventthis,installtheinletandoutletpipesfacingupandinstalltheunitsonaslightuphillslopeofnomorethan1″fromendtoend.Todothis,shimthe2×12frame so that the inlet (east) ends of the sterilizers are lower than the outlet(west) ends. Installing the units in this manner will prevent airlocks fromforming as any trapped air will be pushed through by the flow of water andreleasedthroughthefishtanks.

MainwaterpumpsandUVsterilizers.Sideview.

MainwaterpumpsandUVsterilizers.Topview.

Oncetheframeisinpositionwiththeunitsstrappedintothesemicircleswithoutletsfacingup,constructthetwomanifoldsthatwillconnectthepumpstothesterilizersandthesterilizerstothefishtanks.

Build bothmanifolds out of 4″ pipe, tees and elbows. The two inner UVunitswillconnect to themanifoldsvia4″reducer tees,andthetwoouterunits

connect via 4″ elbows and reducer bushings. The reducer tees, and reducerbushingsare4″×(X)″accordingtothesizeofUVinlets(e.g.iftheUVsterilizershave2″inletandoutletconnections,theteesandbushingsare4″×2″).

The pumps will connect to the inlet manifold via a 4″ reducer tee in thecenterofthemanifold.

Oppositetothis,centeredontheoutletmanifoldisa4″tee,ashortlengthof4″ pipe, a 4″ sweep or elbow and a 4″×3″ reducer coupling. Later, this willconnecttotheundergroundfishtankplumbing.

Place threadedunions andgate valves above the inlets andoutlets of eachunit.Manysterilizerscomewithunionspre-installedforeaseofinstallationandmaintenance.

Buildthemanifoldssymmetricallytoensurethewaterflowrateisrelativelyequalbetweenallunits.Theeasiestmethod is tobuild themanifolds inplace,startingwith theconnections to thesterilizers.Dryfiteverythingbeforegluingandtakecarenottoletexcessgluedripintothesterilizers,gatevalvesorunions.

InstallingtheUVtoFishTankPlumbingDiga6″wideby6″deeptrenchfromtheUVoutletmanifoldtothePurgeTankSPA(justtothewestoftheCFB).ContinuethetrenchtotheSPAsofTanks1,2&3inthatorder.Minimizethesystemheadbysofteningbendsorusingsweepswhereverpossible.SeediagramshowingDWCplumbingonpage105.

Use3″pipetorunundergroundfromtheUVoutletmanifoldtoTank3.JustpastthenorthwestcorneroftheCFB,installa3″×1½″tee,1½″riserpipe,1½″ball valve and 1½″ elbow to connect to the 1½″ bulkhead fitting in theCFB.ThisbypasswillhelptobalancetheflowandallowthetankstobetakenofflinewithoutshuttingoffflowtotheCFBandtroughs.

Installa3″×1½″teenexttotheSPAlocationforthePurgeTankandTanks1&2(threeteestotal).NexttotheSPAlocationforTank3,installasweepanda3″×1½″ bushing. Install four 1½″ riser pipes in the reducer tees and reducerbushing,extendinguptothelipsofthetanks.TherisersmustrisetotouchtheouteredgesofthetanklipssothattheycanbesecuredtothelipswithawoodbackingblockormetalL-bracket.

Cuttheriserpipe12–16″belowthebracket.Installa1½″ballvalveand1½″threadedunionbetween thevalveand thebracket.Using short lengthsofpipe

andanelbow,makeaspoutandfititinthetopofthethreadedunion.Thespoutshouldextend6–12″intothetank.

Tankinletspout.

Onceeverything isglued together, looselysecure the riser to theL-bracketwith galvanized or stainless steel strapping. Keep this loose so that the inletspoutcanbeswivelledwhentheunionisloosened.

Backfill the trench and finish the groundwith a layer of compacted crushgravel.

CalculatingtheSystemHeadNowthat the tank inletplumbing iscomplete,youcanaccuratelycalculate thetotal head of the system and use that data to find a pump that matches the

1.

2.

3.

4.

5.

performance requirements of the system. Remember you will be buying twoidenticalpumps,eachsizedtorunthesystemonitsown.

Calculatingthetotalheadofthistypeofpumpingsystemisacomplexandchallenging task. The pumping system has multiple parallel branches, withdifferentsizesofpipesandfittings,anddifferentflowratesthroughthevariousbranches(e.g.,the3″maindistributionlinemayhaveaflowrate400LPM,butthe 1½″ inlets for the tanks only have⅓ of that). The friction losses of eachbranch need to be calculated separately and some, such as the friction lossesfromtheUVsterilizers,maynotbepublishedbythemanufacturerandcanonlybeestimated.Werecommendhiringaprofessional.

IMPORTANT

Thetotalheadforyoursystemiscalculatedonlyonthepumpsideoftheplumbing:fromthepumpstothefourtanks(notincludingthebypasstotheCFB).Thegravitysideoftheplumbing(fromthetanksthroughthefilterunitstothetroughsandbacktothesump)isnotincludedinthetotalheadcalculation.

Thebasicstepstodeterminethetotalheadofthesystemareasfollows:

For each branch or section of the system, determine the friction losses ofeachfittingin“equivalentfeetofpipe.”Measurethetotallengthofpipeusedineachbranchorsectionandaddtothe“equivalentfeetofpipe”forthatbranch.Usethefollowingcharts(orasprovidedbythemanufacturer) todeterminethehead, indecimal feet,of eachbranchat the flow rateexpected for thatbranch.Measure, indecimal feet, theverticaldistancebetween thepredictedwaterlevelinthesumpandthesuctioninletheightofthepump.Thisisthesuctionhead.Measure, indecimal feet, thedifference inheightbetween thepumpoutletandthefishtankinlets.Thisistheverticalhead.

6. Add the friction lossesof eachbranchor section, the suctionheadand theverticalhead.Thisisthetotalsystemhead.

Forexample,theinletassemblyonTank1hasatotalpipelength(includingequivalentlengthoffittings)ofapproximately18′of1½″schedule40PVC.Ataflowrateof140LPM,thefrictionlossforthisbranchwouldbe1.3′ofhead.

Ideally this process should be repeated for a range of flow rates (as flowincreases,sodoeshead)andtheresultingdataplottedintoagraph.Thiscreatesa“systemcurve”whichisjustlikeapumpcurveexcepttheplottedlinewillcurveintheoppositedirection.

Frictionlossesforschedule40PVCpipe,shownas“feetofheadper100′ofpipe.”

FrictionlossesforcommonPVCfittings,shownas“equivalentlenthofstraightpipe.”

SelectingthePumpsOncethethetotalsystemheadiscalculatedandasystemcurvecreated,thedatacanbeusedtosourceapumpbycomparingtheperformancegraphofthesystemwith that of the pump: the point where the system curve and pump curve

intersectistheoperatingpointofthesystem.Toselectapump,lookforonethatcancreatetheflowofwaterneededatthetotalheadofthesystemplus10%.Forexample,ifthetotalheadis15.5feet,andtheoptimumflowis400LPM,lookforapumpthatwilloutput440LPM@15.5feet.

Asaruleofthumb,itisbettertoslightlyoversizethepumpthanundersizeit,within reason. The pump is going to be on 24 hours a day so it should be asefficientaspossible.ExcessflowcanberoutedthroughthebypassvalveintheCFB.

Therearemanybrandsandmodelsofpumps.Compareasmanyaspossibletoassesstheirperformanceandelectricalconsumption.Lookforpumpsthatwillconsume the least amount of electricity and still do the job. Variable-speedpumps,althoughusuallymoreexpensivethansingle-speedpumps,canbeveryefficientandcanadapttoarangeofflowratesandconditions.

Most pumps used for similar applications are centrifugal pumps with endsuctionandtopdischarge,andmanyof thesecanbemountedvertically.Othertypesofpumphavestrainerbasketsorprimerpotsconnected to themandcanonly be mounted in one direction. If your chosen pump cannot be mountedvertically(sothatitssuctionpipepointsstraightdownintothesump),additionalplumbingmayberequiredtoconnect thepumptotheUVinletmanifold.Thiswill add to the total system head. If possible, choose pumps that have endsuctionandtopdischarge.

We have used Little Giant OPWG series pumps running continuously formorethanfouryearswithnoproblemofanykind.Theyaresingle-speed,low-head, high-volume pumps that are electrically efficient and very reliable.Werecommendthem,thoughtherearemanyotherqualitymanufacturers.

Asdiscussed inChapter 2, twopumps shouldbe installed for redundancy.Bothpumpswillbeconnected to thesystem,butonlyonewillbeoperatingatanytime.ThepumpswillconnecttotheUVinletmanifoldwithawye.Ifitisnot possible to source a symmetrical wye fitting, a tee is acceptable, but thebackuppumpshouldbeconnected to thebranchof the fittingand theprimarypumptothestraightrun.

Construct amount or bracket out of 2×4 between the double joist and thewesternendof thesumpcollar toholdthepumpsinposition.Oncethepumpsare mounted and their suction pipes in place, cut a plywood cover to fit

permanently over the western-most section of the sump, with holes for thesuctionpipes.Waterproofthecoverwithatleasttwocoatsofepoxyresin,thenoptionallypaintit.

Pumpsshouldalwayshavethreadedunionsonbothsuctionandoutletpipesto allow easy removal or cleaning of the pump.They should also have a gatevalveonthedischargepipeandaswingcheckvalveonthebottomofthesuctionpipe,4–6″abovethebottomofthesump.

Place a flow switch between the pumps and the UV inlet manifold. Theswitchwill be connected to themonitoring system later. Use either a paddle-style switch like the Aqualarm flow switch or a flow-through style like thePentair ST9. We use and recommend the Aqualarm flow switch which hasMNPTthreadsonthebottomthatcanbedrilledandtappedintoanexistingpipeorfitintoateewithathreadedbushingofthecorrectsize.

HeatPumpInstallationTheheatpumpmustbesizedandinstalledbyanHVACprofessionaltoensureaccuracyandfunctionality.

Theheatpumpmustbemountedtoasolidlevelbaselocatedjustoutsidethesouthsideofthegreenhousenearthesump.Iftheunitdoesn’tcomeonastand,pouraminimum4″thickcementpadanduseanchorboltstosecureit.Itmusthaveadedicatedelectricalcircuit.

Heatpumpsproducealotofcondensate,soplanfordrainage.Unitstypicallyhaveadrainportonthebottomtoattachahose.

Theheatpumpwillrequireanexternalpumptodrawwaterfromthesumpandcirculate it through theunit.Themin/max flowrate is listed foreachheatpump. Before buying a circulation pump, plan all plumbing according to thefollowingdirectionsandcalculatethetotalheadofthissubsystem.

Awaterfiltermustbeusedontheinletoftheheatpumptoavoidpluggingtheheatexchangerwithsolidsfromthesystem.Weusea200microndiscfilterwhichallowshighflowwithminimalrestriction.

Placetheheatpumpasclosetothesumpaspossibletominimizeheatgain/lossthroughtheplumbingandtoincreasepumpingefficiency(lesshead).Onceit is solidly inplace,diga trenchbetween theunitand thesumpfor thewater

in/out pipes. Pipe sizing depends on the circulation pump discharge and heatpumpconnections.Makethetrenchbigenoughforboththeheatpumppipesandthecisternpipes(seeCisternInstallationbelow).Installbothatthesametimeifpossible. Make the trench wider than necessary between the sump thegreenhouse wall in order to easily work on the connections and so that thecirculationpumpcanfit.

Usingtreatedlumberandplywood,shoreupthewallsofthetrenchbetweenthe sump and the baseboard of the greenhouse to create a service box foraccessing thevalvesand thecirculationpump.Makea lidoutof¾″plywood.Alternatively, a prefabricated irrigation valve box can be used. If installing acistern,maketheserviceboxlargeenoughforbothsetsofpipes,withsufficientspacefortighteningfourbulkheadfittings.

Heatpumpandcisternvalveservicebox.

Connectthesuctionanddischargepipestotheinlet/outletoftheheatpumpwith threaded unions and gate valves on both. The suction pipe connects thesumptotheinletoftheheatpumpviathecirculationpump.Thedischargepipeconnectstheheatpumpoutlettothesump.

Build a bypass port between the inlet and outlet pipes to adjust thewaterflow rate through the unit if necessary, and auxiliary ports between the gatevalves and the unit for backflushing and cleaning the heat exchanger (seeChapter11).

Heatpumpbypass,inletfilterandflushingports.

Connectthe200microndiscfiltertotheinletport.Run the suction/dischargepipesunderground through the trench andunder

thebaseboardofthegreenhousetothesouthwallofthesump.Theheightofthepipes isnotcritical,but theyshould run through thewallof the sump,not the

1.2.

3.

collar.Oncetheconnectionlocationisdetermined,drillpilotholesthroughthesump, thenuseaholesawfrom inside thesump. Install theclampringon thebulkhead outside the sump; install the gasket inside against the LDPE liner.Remember:socksonlywhenstandingorwalkingonLDPE.

Placeballorgatevalvesonbothsuctionanddischargepipesintheservicebox outside the sump.Connect the circulation pump to the suction pipe usingthreaded unions. If the pump is powered by an outlet, run the power cordthroughanelectrical conduit in the trench to thenearestoutlet. If thepump isautomaticallyswitchedbytheheatpump,theHVACtechwillwireittotheheatpumpcontrol.

Connectthedischargepipetothecorrespondingbulkheadandvalve.Insidethesump,connectashortlengthofpipeandanelbowtothesuctionbulkheadinordertodrawwaterfromthebottomofthesumpnearthe4″hydroponicreturnpipe.Installaswingcheckvalveonthebottomofthesuctionpipe.

CisternInstallationA cistern is optional but highly recommended. The cistern should be at least4,000liters(biggerisbetter)andlocatednearthesump,outsidethegreenhouse,withthetopatorbelowgroundlevelofthegreenhouse.Thislikelywillrequireexcavation.Use a 3–4″ layer of bedding sand under the cistern to ensure it iswellseated.

Acisternservesthreemainfunctions:

Itcanbeusedtocollectrainwatertofeedthesystem.Itcanbeusedasastoragetankforwaterfromthesystem.This isausefulfeaturethatcansaveaconsiderablequantityofwaterwhendoingaSaltBathTreatmentonthefish(seeChapter8)orifyouneedtoperformrepairs.ItcanbeusedasanoverflowreservoirtopreventthesumpfromoverflowingduetotheDrainDownEffectinapoweroutageorpumpfailure(seeChapter2).

A2″overflow standpipe in the sump, similar to the troughdrains,will letexcesswaterflowintothecisternwhenthewaterlevelinthesumpistoohighforanyreason.Asubmersiblepumpinthecisternisusedtopumpwaterbackto

the sump as needed and is controlled by a switch or timer in the greenhouse.Rainwater can be collected in the cistern via gutters on the greenhousewhichcanconnectintotheoverflowpipeordirectlyintothetopofthecistern.

Oncethecisternisinplace,digatrenchforthe2″overflowand1½″returnpipes. Terminate the trench at the in-ground service box that was installedpreviouslyfortheheatpump.Installtheoverflowandreturnpipes.Theheightofthereturnpipeisnotcritical,butthebulkheadfortheoverflowpipemustbeatleast 4″ below the intendedmaximumwater level in the sump,with the pipesloped gently downhill towards the cistern to drain properly. Run the powercable for the pump through a conduit in the trench and up the inside of thegreenhouseonanarch.Laterthiswillbewiredtoaswitch.

Useaholesawtoinstalltwobulkheadsthroughthesouthwallofthesump,beside theheatpumpconnections.Drill from inside the sumpwithpilot holesfirst.Leaveenoughroombetweenthebulkheadsforthevalvesoneachpipetoturn without contacting each other. Install the clamp ring on the bulkheadoutsidethesump.InstallthegasketinsideagainsttheLDPEliner.

Connectballorgatevalvestothebulkheadsontheoutsideofthesump,thenconnect the overflow and return pipes to the valves. Inside the sump,make astandpipedrainoutofpipeandanelbow,likethetroughdrains,andattachittothe bulkhead fitting of the overflow pipe. The top of the standpipe should beslightlyhigherthantheintendedwaterlevelinthesump.

Connect the overflow pipe to the top of the cistern with a bulkhead orUniseal.Drillasecondholeinthecisternforthereturnpipe,justlargeenoughforthepipetoslidethroughwithoutallowingdebrisintothetank.DonotuseabulkheadorUniseal in thisholeas thedischargepipeneedstomovefreelyupanddownthroughtheholeinordertoinstallorremovethepump.Theholesintothecisternmustnotbeintheremovablelid.

Once theplumbing layout is known, calculate the total head for the returnpipeandsourceapumpwithappropriateperformance.Youdonotneedahigh-LPMpumpbuttheslowerthepump,thelongeritwilltaketomovewaterfromthecistern.Thepumpmustbesubmersible,withafloatswitchtopreventitfromrunningdry.

To install thepump, connect a riser to itsdischargeoutlet so that it is justlongenoughtoreachthroughtheholeinthetopofthecisternwhenthepumpis

sittingon thebottom. Install a swingcheckvalveat thebottomof the riser topreventwater from the sumpdraining back into the cisternwhen the pump isturned off. Zip-tie the pump’s power cable to the riser and secure a length ofwaterproofrope(e.g.,nylon)tothepumptoassistwithraisingandlowering.

Cisterninstallation.Notetheserviceboxbetweensumpandgreenhousewall.

Withthelidremoved,lowerthepumpthroughthecistern’stopaccessport,thenslidetheriserpipeandpowercablebackupthroughthepredrilledholesothattheriserextendsoutoftheholeby4–6″withthepumpsittingonthebottomof the cistern. Clamp a flexible rubber coupling to the top of the riser, thenconnecttherisertothereturnpipeinthetrenchwithanelbow.Ifthepumpeverneeds to be serviced or replaced, simply unclamp the coupling, push the riserbackthroughtheholeandusetheropetopull thewholerigoutof thecistern.Leavetheropehangingoutoftheaccessportandsecureitsoitcannotfallintothecistern.

Run thepowercable throughconduit into thegreenhouse.Run theconduitand cable up one of the greenhouse arches.Wire a shutoff switch and a solidstate timer inaweatherproof junctionboxattached to thearch.The timerwillensure that the pump cannot be accidentally left on, wasting electricity andpotentiallydamagingthepump.

SeedlingTableConstructionTheSeedlingTablewillbelocatedinthenorthwestcorner.Thetableis36″widewhichallowsforthreetraystobefitontheir11″side(plus3″ofwiggleroom).Thiswillallowyoutolocatethetableagainstthesideofthegreenhouseandstillhave easy access to all trays from one side. It is also an excellent width forsupplementallighting.Notethatifusingatowersystem,alargerSeedlingTablemayberequiredduetothepotentiallylargerquantityofplantsites.

Thetablecanbeconstructedinanymannerofyourchoosing,solongasitissturdy. It should be one level, not stacked, and a comfortableworking height,usuallyaroundwaisthigh.Asimplemethod,whichweused,istobuildabasicframeand legsoutof2×4with½″plywoodas the table top.All edgesof thetable shouldhavea2″plywood lip.Fill all topseamsandedgeswithamold-resistant caulk. The table should be waterproof, which can be accomplishedeitherwithamembrane(LDPEworkswell)orbypaintingliquidrubberontothetable topandinsideof the lips.Weusedliquidrubber.Buildthe tablessothattheyareslightlyslopedtowardsonecornerforeasydrainage.

Place¾″ thru-hulldrains in eachof theoutsidecornerswherewaterpoolsanduse¾″hose to connect thedrainsunder the table towards thewall of thegreenhouse.Digthehoseintothegroundunderthegreenhousewallsothatthewaterwillpercolateintotheperimeterdrain.

Install400WHIDlightsperthelayoutshownintheDWCoverviewdiagramonpage30.Eachlightshouldcoveramaximumtablespanof6′.Theinstallationofthelightswilldependonthemanufactureofyourchosenunits.Twosimpleinstallationmethodsaretohangthelightsonchainsfromthegreenhouseframeortobuild2×4supportsoverthetable.Notethat,unlikethesupplementallightsover the troughs, these lights will not move laterally. The bulbs will beapproximately 2–3′ over the plants. Ideally, you should be able to adjust theheightasneeded.

Ifusingheatingmats(whichwerecommend),installthemnow.

WorkbenchConstructionThe workbench is a primary work area in the greenhouse. Seeding andtransplantingarebothdonehere.Constructa3′×6′workbenchinanymannerof

yourchoosing,likelythesamemethodastheSeedlingTable:2×4framingwith½″plywoodtopand2″plywoodlip.Thiswillcomfortablyfita2′×4′raftwithextra work space (needed particularly for transplanting). It should be acomfortable working height for you, likely the same height as the SeedlingTable.Sealthebenchwithamembraneorliquidrubber.Slopethetableslightlytowardsthenorthwall(nomorethan1″slope)andinstalla¾″drainviaathru-hullandhosetodrainexcesswaterintotheperimeterdrain.

Foratowersystem,werecommenda3′×8′tabletoallowforeasyplantingin5′towers.

Walk-inCoolerInstallationWe recommend you consider a walk-in cooler mandatory. You will beproducinglargequantitiesofproducethatarebeststoredinstackabletotesinacooleradjoiningtheoutsideofthegreenhouse.Ifyouaresellingyourfishfresh(notfrozen),refrigerationisalsorequired.

For the production you can expect from our design, we recommend yourcooler be a minimum of 80 sq. ft. Coolers are very simple, and a good oneshouldlastmanyyearsifproperlyinstalledandnotabused.Theunitsconsistofinterlocking insulated wall panels that can be connected into differentconfigurations. The refrigeration component will need to be installed by anHVACprofessional.

Newcoolerscanbeextremelyexpensive.Wesuggest sourcingausedunitthat is inspectedbyanHVACprofessionalprior topurchase.Allmodernunitsareaircooled,meaningtheyuseairtocooltherefrigerationpump.Someolderunitsarewatercooledandthesetendtobeinefficient,wastinghugevolumesofwater.Donotbuyawater-cooledunit.

The cooler should be installed outside the west endwall. While it can beinstalledanywherenearthegreenhouse,thislocationisthemostconvenientforloading.Itcanbe locatedoneither thenorthorsouthsideof thewestendwalldoors.Ours is located on the south side; thus,we have shown it there in thisbook.

The cooler should be installed on a standard concrete pad (minimum 4″).When planning the location of the cooler,make sure you leave enough room

between the cooler and the sliding greenhouse doors to allow room for theGerminationChamber.

Werecommendthatyouhireaprofessionaltobuildyourcooler.Thepanelscanbeinstalledinavarietyoflayoutsaccordingtoyourneeds,andthedoorcanbelocatedwhereyouprefer.Installthedoorsothatitcanbeaccessedeasilyandwithoutinterferingwithsurroundingworkspace.Ourdoorisonthewesternendofthecooler.

IMPORTANT

TherefrigerationsystemofthecoolermustbeinstalledbyanHVACprofessional.Donotattemptanyworkinvolvingtherefrigerantusedinthecooler.Therefrigerantcanbetoxicandisextremelydangerous.

The compressor on the roof of the cooler must be protected from theelements.Thesimplestmethod,whichweused,istoinstallabasiclean-toroofoff the endwall of the greenhouse. You can use any materials you deemappropriate.Weused6×6postswith2×4raftersandmetalroofing.Thestructuredoesnotrequirewalls;simplybuildanoverhangofatleast2′onallthreesides.

GerminationChamberConstructionThe Germination Chamber is attached to the side of the cooler nearest thegreenhouseslidingdoors,unlessyouplanonusingaportableairconditionertochillthechamber,inwhichcaseitcanbebuiltanywherenearby.AsdiscussedinChapter 2, the chamber must be capable of holding at least 15 trays for ourdesign.Additional traysmaybe required fora towersystem.TheGerminationChamber described here is capable of holding 18 trays on two levels (9 perlevel).

Bothgermination tablesare litwith three3′T5 fluorescent lights (six totallightsforthechamber).Thelowerlightsaremountedtothebottomoftheupper

table;theupperlightsaremountedtocrossbracesjustbelowtheroof.Thelightsare controlled by a timer. The temperature is controlled by a thermostaticcontroller.

Thechamber iscooledbystealingcoldair fromthecooler.Coldairentersthechamberatthebottom,andwarmerairreturnstothecooleratthetopofthechamber.Ifyouopttonotinstallacooler,youwillneedasmallwindow-mountair conditioner to cool the chamber. The chamber is heated either via a smallelectricheateratthebottomorviaheatingmatsunderthetrays.

Nowateringoccursinthechamber,sowhilenodrainsareneeded,thelevelsshouldstillbewaterprooftopreventthewoodfromdeteriorating.Allelectronicsand controllers should bewall-mounted, and just like in the greenhouse, onlyGFCIoutletsshouldbeused.

The two 4″ holes cut through the cooler wall are fitted with backdraftdampers to ensure one-way operation and tominimize unintended air leakagebetweenthechamberandthecooler.

Build the two36″by72″ tables for the traysoutof2×4sand½″plywoodusingthesameconstructionastheSeedlingTable.

Build a frame out of 2×4s against the side of the cooler. The interiordimensionsare76″wideby44″deepby96″high.The interiorwidth/depth isgreaterthanthetabledimensionstoallowroomforinsulationagainstthewallsandairgapsatthefrontandbacktoallowaircirculation.

Slopetheroofslightlyawayfromthecoolertoshedrainandframeasetofdoorsonthefront.Theroofshouldoverhangthethreesidesbyatleast12″.Thedoorsmustbeabletoshutoutdrafts.Useweatherstripping.

Sheath the walls and roof with ½″ plywood and caulk all the joints withsiliconesealant.Shingletheroofandpaintthesidesanddoorswithatleastthreecoatsofexteriorpaint.

Constructtheinnerbracingoutof2×4stoholdthetables.Bothtablesneeda2–3″ gap at the front (between the tables and doors) and back (between thetablesandcooler)toallowaircirculation.Thelowertableis30″offthegroundifusingaspaceheater.Itcanbelowerifseedlingmatsareused.Thebottomofthe upper table frame is 24″ from the top of the lower table. This is theappropriatedistancetomountthelowerlights.Installtwocrossbracesacrossthechamber(lefttoright)24″abovethetopoftheuppertabletomounttheupper

lights.Ifyouareusingawindow-mountA/Cunittocoolthechamber,installitina

sidewallabovetheuppertable.Usesmallfanstocirculatethecoldairaroundthechamber.

Beforeinstallingthetables,caulkallinteriorseamsandjoints,theninsulatethesides,doorsandroofbygluing2″styrofoampanelstotheinside.Beprecisewiththecutstoavoidgaps.Noinsulationisrequiredagainstthecooler.

Runpower to thechamber.UseGFCIoutlets.Thechamberand thecoolerevaporatorfan(insidethecooler)canshareacircuitifthefanis120v.Typicallya cooler compressor (on top of the cooler),which is a large electrical load, is240vandrequiresadedicatedcircuit.

Useaholesawtocuta4″holethroughthecoolerinthecenterbottomofthebackwall, below the lower table.Cut another 4″ hole in the top center of thechamber, above the cross braces for the upper lights. Install a 4″ backdraftdamperinthetopholeinsidethechamber.Thisallowsairtoonlyflowintothecooler.Installaseconddamperinthelowerholeinsidethecooler.Thisallowsairtoonlyflowintothechamber.Mounta4″inlinefan(minimum100CFM)onto the bottom damper so that it blows cool air into the chamber. The air isforceduparoundthetablesandouttheupperholebackintothecooler.

Installthetablesleavinggapsatthefrontandbackforcirculation.Mount the thermostat against the back wall, just below the bottom of the

uppertable,andconnectthefanandheatertoit.PlugthethermostatintoaGFCIoutlet.

The fluorescent lights can eitherbe chained together forpowerorpluggedindividuallyintoapowerbar.Ineithercase,thelightsareconnectedviaatimerpluggedintoaGFCIoutlet.

B

ToolsoftheTrade

YTHEENDOFCHAPTER4,youshouldhaveacompletedgreenhousewithallmajorconstructioncompleted.Thegreenhouse is fullybuiltand installed,

including troughs, tanks, filter and sterilization systems, seedling and workareas,walk-in coolerwith adjoiningGerminationChamber, and all plumbing,aeration and electrical. Fully oxygenated water, filtered by the filtration unitsand sterilized by the UV units, should flow freely through the whole systemwhenthepumpsareturnedon(seeChapter7).

This chapter is a component list for the additionalmajor tools thatwill beused in the system.With the exceptionof the freezer,we consider all tools inthissectiontobemandatoryforconsistentlong-termsuccess.

ShadeClothShade cloth is a woven netting that reduces the intensity of light during thehotter times of year. It is typically made of polyethylene (PE) and comes invarious opacities that specify the amount of light blocked by the cloth (30%cloth will block 30% of the light that hits it). Good-quality shade cloth iscustomizableinitsdimensions,sewnonalledges,UVstabilized,hasnumerousgrommetstoserveasanchorpointsandhasalifeexpectancyofatleast10years.

The use of the shade cloth will be highly dependent on your latitude andlocalenvironmentalconditions.Ingeneral,werecommendinstallingshadeclothwhendaily temperatures are above25°C (77°F).Onour farm in southwesternCanada, we usually have cloth installed from around early July to earlySeptember.

Intemperateorcolderclimates,30%opacitywillusuallysuffice.Inwarmerclimateswhere the sun ismore intense and for longer daily photoperiods,werecommend50%opacity.Theshadeclothshouldbesized tocoveryourentiregreenhouse, down to ground level, excluding the endwalls (unless yourgreenhouse is oriented north-south, in which case the south endwall requiresshading). Itwillbeone largeclothandwillanchoralong the longsidesof thestructure.

Our50%opacityshadecloth.

OurclothismadebyAmericanNettings&Fabric,Inc.Therearenumerousothercompaniesthatproducesimilarproducts.

Install the shade cloth by laying it out along one side of the greenhouse,affixingropestoseveralgrommetsandthrowingtheropesoverthegreenhouse.Pulltheropesfromtheoppositesidetosituatethecloth,takingcarenottosnagorteartheclothorgreenhousecovering.Attheendofthehotseason,uninstalltheclothwhenitisdryandstoreinadrylocation.

BackupOxygenandPowerOneof thegreatest threats toyourfarmisapoweroutage.Anaquaponicfarm

reliesonconstantelectricityforoperation.Periodicpoweroutageshappeninallpowergrids,sopreparingforthemisessential.

The single most threatening consequence of a power outage is oxygendepletion. Your system can survive for a prolonged period without watermovementandfiltration,buttheoxygeninthewaterwillberapidlyconsumedbythefish,plantsandbacteria.Fishinparticularrequireconstanthighlevelsofoxygen and will likely start dying within 30 minutes without replacementoxygen.Thisholdstrueforalltypesofsystemsincludingtowers.

One solution is to install a backup generator system. There are numeroustypes of generators available for such purposes, and you would need to sizeyoursaccordingtoyourelectricalload.Notallitemsneedtobeconnectedtothegenerator,asnotallarevital.Themostcrucialitemstobackuparetheaerators,water pumps, propane heater and, in the case of double-poly greenhouses, thepolyinflationblower.

Thedownsides toageneratorare that theycanbeveryexpensiveand, likeall internal combustion engines, are not 100% reliable. Rather than using agenerator,werecommendinstallingabackupoxygensystem.Evenifyouopttoinstallagenerator,werecommendalsoinstallingabackupoxygensystem.

In addition to being the best remedy for power outages, a backup oxygensystemisalsoveryhandyforsupplementingoxygentofishtanksduringtimeswhen the tanks are takenoffline from themain system, such aswhendoing aSaltBathTreatmentorwhennewcohortsarequarantined.

Abackupoxygensystemisveryinexpensiveandisvirtually100%effectivein a power outage. The backup system is simply compressed tanks of pureoxygen that are set to provide oxygen to the fish tanks and theMBBR if thepowergoesout.TheMBBRisvitalas it is the largesthost forbacteriawhichalso consume considerable quantities of oxygen. The frequency and length ofpower outages in your area will dictate the volume of the oxygen tanks.Wesuggesthavingatleasttwo“T”or“K”sizetankssothatyoucanswapthemoutforrefillingasneeded.One“T”or“K”sizetankholdsenoughoxygentokeepthefishandbacteriaaliveforabout24hourswhenusingmicro-bubblediffusers.Werentourtanksfromalocalweldingshopandswapthemoutforfreshtanksasneeded.

The tanksmustbe locatedoutside thegreenhouse inawell-ventilatedarea

that is protected from the weather. The tanks must not be located in thegreenhouseoranywherenearfuel-burningappliances.

The tanks are connected to a pressure regulator that controls the outletpressure.Settheregulatorat40–50psi.Theregulatorisconnectedtoasolenoidvalve that is “normally open” (a valve that is open when the solenoid is notpowered). During regular operation, with power running to the solenoid, thevalve is closed and no oxygen flows. When power no longer reaches thesolenoid,asinapoweroutage,thevalveautomaticallyopens,allowingoxygentoflow.

The solenoid valve should be wired by your electrician to a switch andpower supply. We use and recommend Jefferson solenoid valve # ZC-1327BN402TINA-O. If using any other solenoid valve, make sure it is thecorrect voltage and operating pressure and that it is specifically rated for usewithoxygen.

The outlet of the solenoid valve is connected to a five-port flow metermanifold which can be located inside the greenhouse. One port controls theoxygenflowto theMBBR,and theotherfourcontrol flowtoeachof thefourfish tanks via¼″ vinyl tubing.Run the tubing through conduit from the flowmetermanifold,overheadthroughthearches,droppingdownintoeachtankandtheCFB.Drill a¼″hole at the top center of the east sideof theCFB for thetubing.Once in place, seal the inside and outside around the tubewith epoxyresin.

Toincreasetheefficiencyofoxygentransferandextendtheoperatingtimeof the backup oxygen system, use ultra-fine pore diffusers rather than themedium-porediffusersused in the troughs.We recommendSweetwaterMicroBubbleDiffusers.

Backupoxygensystem:oxygentank,pressureregulator,solenoidvalveandflowmetermanifold.

Intheeventofapoweroutage,itisstillcrucialthatyouimmediatelygotothe greenhouse to confirm the backup oxygen isworking. The backup systemrecommended here is very simple with little chance of failing, but theconsequencesaredire,soyoushouldalwaysdouble-check.Youwillknowthatthepowerisoutbecauseofthemonitoringsystem.

We recommend linking the backup oxygen system with the monitoringsystemtoautomaticallytriggertheoxygenineventsotherthanapowerfailure,suchaspumporaeratorfailure.

MonitoringSystemAmonitoringsystemisessential foryourfarm.Oneof theprimarybenefits toaquaponicproductionishowlittleworkisrequiredtoproducelargequantitiesoffood compared with traditional soil farming. The flip side of this is that the

majorityof the168hours inaweekarenotspent in thegreenhouse.Havingamonitoring system to immediately alert you to something going wrong isthereforeessentialregardlessofthebackupsystemsyouhaveinplace.Youneedtoknowifsomethingisamiss.

There are numerous monitoring systems on the market that you can use.Essentially what you require is an autodialer that you program with specificparameterstonotifyyouifitreadsanythingoutsidethoseparameters.Someareconnected to the internet and use data to contact you, some use telephone orcellular networks, and some connect via satellite. Internet connectionswill bethe cheapest to operate; satellite the most expensive. There are a variety ofoptionsforhowtobenotified,includingtextmessage,emailorphone.

WeuseandrecommendtheWeb600monitoringsystembySensaphone.Itisasmallnetwork-enabledunitthatconnectstoarouterandcansendtextmessageoremailalertstoanydeviceviatheinternet.Internetserviceonsiteisrequired.TheWeb600hasarowofcontactterminalstowhichavarietyofswitchesandprobes can be connected, such as flow or pressure switches, temperature orhumidityprobes,andsmokealarmsormotiondetectors.

It also has a built in SPST relay outputwhich is capable of triggering thebackup oxygen system. This is particularly useful in situations other than apower failure that would result in low oxygen conditions, such as pump oraeratorfailure.TheWeb600isprogrammedbyaccessingthedevicefromawebbrowseronyour computer andcanbe setup to escalate alarmnotifications tomultiplecontactprofiles.

The crucial parameters to monitor are power, water flow and aeration.Optionally,youcanalsomonitorwatertemperature,airtemperature,motion(forsecurity)ormanyotherthingsofyourchoosing.Power,waterflowandaerationaremandatory.

Web600monitoringsystemwithbatterybackup(right)andaerationpressureswitch(left).

Tomonitorpower,youwillneedabatterybackup(thisisanextraitemwiththeWeb600).Notethatthenetworkrouterthemonitoringsystemisconnectedtomustalsohaveabatterybackup(UPS)foralarmstobesentinapoweroutage.

Waterflowismonitoredwithaflowswitchlocatedbetweenthepumpsandthe UV inlet manifold. We recommend the Aqualarm 10235 Flow Detectorwhichisasimpleon/offpaddleswitchdesignedtobedrilledandtappedintoapipeorthreadedintothebranchofateefitting.Iftheflowdropsbelow40LPM,theswitchopensandanalarmistriggered.

Aeration is monitored with an air pressure switch connected to the airdistributionsystem.Connectanextralengthof¼″tubingtotheairdistributionpipelocatedinthesump.Runthetubingthroughthewestendofthesumpnearthemonitoringequipmentandconnectittothehighsideofthepressureswitch.We recommend using a low-pressure diaphragm switch such as the MDS-6

(compact pre-set) or theModel 1638-10 (adjustable) fromDwyer Instruments.Thepressure switchmusthave a setpointof10″WC (WaterColumn)or less.Airpressureinthedistributionpipekeepstheswitchinanopenposition.Iftheaerator fails for any reason, the drop in pressurewill close the switch and themonitoringsystemwillsendanalarmnotification.

Aqualarm10235Flowswitch.

We highly recommend linking the monitoring system with the backupoxygensystemincaseofpumporaeratorfailure.Thebuilt-inrelayoutputinthemonitoringsystemcanbeprogrammed to triggerelectronicequipment suchasthe oxygen solenoid valve. To do this, your electrician will need to wire a“normally closed” relay switch (with a control voltageof30v/1Aor less) into

thebackupoxygenpowersupplyandrunacontrolwiretotheWeb600.Duringnormal operations, the relay will allow power to flow to the solenoid valve.When a programmed alarm occurs, themonitoring systemwill send a controlsignaltotherelaywhichwillopentheswitchandcutoffpowertothesolenoid,whichinturnwillopenitsvalveandsendoxygentothetanks.

pHControllerpHmonitoringandcontroliscriticalforthesystemtothrive.Itisnotacceptableto just make daily manual corrections. There are only a few commerciallyavailable monitors that monitor and control pH.We use and recommend theBluelab pH Controller which has an integrated peristaltic pump with user-replaceablecomponents, andwhencalibratedproperly,wehave found it tobeveryreliable.

Calibration is simple and done monthly. Use only Bluelab calibrationstandards. We have found other brands of calibration standards, althoughcheaper,tobeinaccurate.Inadditiontoregularcalibration,itismandatorythatyou use chemical pH tests to verify that the electronic monitor is readingcorrectlyas,evenifregularlycalibrated,itispossibleforelectronicmonitorstogive inaccurate readings. Chemical kits, while less precise than electronicmonitors (as the reading is given in a color gradient), are farmore reliable toconfirmtheapproximatepH.

pH ismonitored in thesumpwith theprobe locatednear thepump intakes(justbefore thewater leaves thesump).ThepHadjustingchemicalsshouldbeintroduced to the sump at the east end, near the return from the hydroponictroughs, to allow proper mixing with the system water. The tubing that issupplied with the controller to adjust pH is run along the inside of the sumpcollartotheeastendofthesumpnearthereturnfromthehydroponictroughsfordistribution.Keeptheendofthetubeabovethewater.

BluelabpHController.

DissolvedOxygenMeterA Dissolved Oxygen (DO) meter monitors the level of available oxygen inwater. It is used tomeasure the oxygen in the fish tanks (including thePurgeTank)andwhentransportingcohortsoffingerlings.

Whenwefirststarted,webelievedthistobeacrucialpieceofhardwareandbought a very expensive unit.We do not recommend this unless you plan tokeepanongoinglogofyourDOlevels(wedonot).WhileitisimportanttohaveaDOmeter at the establishment of the system and to transport fingerlings toyourfarm,youwillnotrequireanexpensiveunitcapableofaveryhighdegreeofaccuracy.

We use an Orion Star A2235 portable DO meter that cost more thanC$1,500.Wemust calibrate theunit before everyuse, and thevery expensiveprobesmustbereplacedannually.Wedonotrecommenditorunitslikeit.Anexample of ameterwe recommend is theOxyguardPolarisDOmeter,whichcostsapproximatelyC$900.

WaterTestingKit

Water testing kits aremandatory and need not be complicated or fancy.Yourkits must be able to test for ammonia, nitrites, nitrates, iron, phosphorous,calcium, hardness and potassium. It is uncommon for potassium testing to beincludinginageneraltestingkit,soyouwillneedastand-alonepotassiumkit.

WerecommendtheNutrafinA7860mastertestkitasitcontainseverythingyou need except the potassium test.We also recommend the API FreshwaterMasterTestKit.TheAPIkit testsonly forpH,ammonia,nitritesandnitrates,but we have found the pH and ammonia tests to be more accurate than theNutrafin.Forpotassium,werecommendtheLamotte3138-01PotassiumKit.

Ourwatertestingkits.

Ingeneral,testingkitsshouldbereplacedoneyearafteropening.Likemanyof thesuggestedcomponents,we recommendpurchasing fromPentairAquaticEco-Systems.

SeedlingTraysandDomesYouwillbeusingstandard11″×22″nurserytraysforgerminationandseedlinggrowth.Ourdesignisbasedaroundtraysthatcontain98cellspertray.Wefindthese to have the ideal spacing for growing seedlings up to transplant sizewithoutovercrowdingorwastingspace.

There is a variety of quality in trays. Cheaper trays will wear out morerapidly and may be more frustrating to use. You will need to experiment todiscernwhichtraysworkbestforyou.Traysareoftenavailableatawholesalerateforcasesof500.Nomatterthequalityofthetrayorhowyouusethem,theywillwearout,sowerecommendbuyingacaseonceyouhavedeterminedyourdesiredtray.

SubstratesYou will need two different types of substrate: a growing substrate forgermination/seedlings and a substrate for transplanting seedlings into net pots.Substratesmustbe freeof residual salts (common incheapercococoirmixes)andpHneutral.

The common choices for a growing substrate are a peat-based potting soilsuchasPro-Mixorcococoir(groundupcoconuthusks).Wehavefoundbothtowork.WeusePro-Mixfor thegrowingsubstrateaswehave found itprovidesbetter germination and it is less expensive. The downside is that peat-basedmixes are less environmentally friendly as, unlike coco coir, they are non-renewable.

The transplanting substrate is used when transplanting seedlings into netpots.Ithelpstopreventthegrowingsubstrateintheseedlingplugfromerodingintothesystemduetothevigorousmixingactionoftheairstonesinthetroughs.Erosion causes poor growth and an accumulation of growing substrate on thebottomofthetroughswhichleadstoanaerobiczonesandimpairednitrificationas thebiofilmissmothered.Thetransplantingsubstrate,whichisplacedin thebottom of the net pot before inserting the seedling,must be coarse enough towithstandtheerodingactionoftheairstones.

We have experimented with a variety of transplanting substrates. Mineralwool,alsocalledrockwool,isthebestatholdingtheseedlingplugtogether,butit has an unacceptably high environmental cost to manufacture, does not

1.2.

3.4.

5.

6.

decomposeincompostandcannotbeusedinorganicproduction.Expandedclaypebblesworkwellandarereusablebutrequireadditionallabortorecoverthemafterharvestingandtowashthembeforereuse.

Ourchoice for transplantingsubstrate isverycoarsecococoirchipswhichkeeptheseedlingplugsintact,canbecompostedwiththerootballsafterharvestandareanenvironmentallyfriendlyrenewableresource.

DibblerPlateTo speed up the process of “dibbling” (poking shallow holes for seeds ingrowingmedia),makeadibblerplatethatcandoawholetraywithonepush.

Cuttwo11″×22″piecesof½″plywood.Useaseedlingtraytomarkthecenterofeachcellthroughthedrainageholesontoonepieceofplywood.Drill¼″holesthrougheachmark.Glue thesecondpieceofplywood to the first.Ensure theyarealignedandclampthemwhiledrying.Beforethegluesets,affixa1″longpieceof¼″dowelrodineveryholewithadabofglueontheendofeach.Onceallgluedries,saturatethedibblerplatewithepoxyresintowaterproofitandallowtocurefor24hoursbeforeuse.

Dibblerplate.

NetPotsOurdesignuses2″netpots,sometimescalledslitpots,whichare2″wideatthetopby2″deepandhaveasmallliparoundtopedgetoholdthepotintheraft.Youwillneedenoughforthesystemplusatleast25%moreassomewillalwaysbeinthecleaningprocess.Forourdesign,youwillneedatleast7,500netpots.

TotesTotesareacommonitemonmostfamily-sizedfarms.Theyareusedforawidevarietyofpurposesfromharvestingandstoringproducetotransportingitemstocustomers.Thesizeofthetotesdependsmostlyonwhatiscomfortableforyou

tomovewhenloaded.Ingeneral,werecommendtotesthatarebetween40–70liters. We suggest purchasing higher-quality totes made of non-rigid plastic.Rigid plastic will crack and split with ongoing UV and cold exposure. Werecommend Rubbermaid Roughneck Storage Boxes which are highly durableandtypicallyretailforunder$10.

PackagingWetriedmanythingstoavoidusingplasticbags,butinourexperiencetheyareanecessaryevil.Plasticbagswillkeepdelicateherbsandsaladmixfromdryingoutduringtransport,andmostendcustomerswillwantabagwhensellingatamarket.Unlessyouaresellinginbulktoalargewholesalebuyer,youwilllikelyrequireplasticbags.Whatyourequirewilldependonyourmarketand/orhowyouaremarketingyourfood.Weuseseveralsizesofbags:smallforpreweigheditems such as herbs, mid-size for salad mixes and larger for head lettuce,romaineheartsandlivingbutterlettuce.

Ourwell-usedsaladspinner.

There are plant-based alternatives to plastic that are acceptable for storingfood, but they tend to be expensive,weak and not always as environmentallyfriendlyastheymightseem.

SaladDryerAcommercialsizesaladspinner/dryerisnecessaryifyouplanonmakingsaladmixes.WeuseaDynamicTM20litermanualsaladdryerwhichisalsoavailablewithamotor.Saladdryersarebestsourcedfromrestaurantequipmentsuppliers.

ScalesYouwillusetwoscales:alow-weighthigher-resolutionscale(~20kg×1g)forweighingproduceand individual fishandahigh-weight lower-resolutionscale(~100kg×20g)forfishsampling(seeChapter8).Werecommendsplash-proof

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orwaterproofbenchscales.Analogue(slidingbeam)anddigitalscalesarebothfinebut ifnot resistant tomoisturewill rustandmalfunctioneventually in thehumidgreenhouseenvironment.

KnivesandScissorsKnivesand/orscissorswillbeusedfrequently,especiallyforharvesting.Thereareawidevarietyofoptionsavailable.Wehavetriedmanytypesofknifeandpreferusinghigh-qualityharvestingscissors.

FishingNetsandTankCoversYouwill need four fishing nets for grading, transfers andmortality removals.Onenetwillbededicatedtoeachtanktopreventthespreadofdiseasefromtankto tank.Look fora long-handledmonorail typenet,withadeep,knotlessbag,suchastheDN33DMonorailNetfromPentair.

Tankcoversarerecommendedas theykeepfriskyfishfromleapingoutofthe tanks (which can happen surprisingly often), and they provide extra shadeandcomfortfor thefishwhichhelps topreventstress. Ifyouarehandywithasewing machine, they can be stitched together from shade cloth and adrawstring,ortheycanbepurchasedfromPentair.

CleaningBrushesYouwillneedthefollowingbrushes:

4 brusheswith long handles, one dedicated to each fish tank.The brushesmustbeabletoreachthedrainofthetank;6′handlesarejustaboutright.1brushwithalonghandleforcleaningtheinsideandbottomoftheRFS.A1–2′handleisideal.1ormoreshort-handledbrushesforgeneralmaintenanceandcleaning.1ormorelong-handledbrushesforcleaningrafts(dependingonhowmanypeopledothisjobatthesametime).1regulardishbrushforcleaningharvestedfish.

Allof thebrushesshouldbesoftbristled.Donotusemetalor rigidplasticbristlesforanyjob.

Oneofourhomemadefishtankcovers.

WashingMachineAwashingmachineisoptionalbuthighlyrecommendedtowashnetpots.It ispossible to do this job by hand, but it will add considerable labor. Only useunscented,non-toxic,biodegradablelaundrysoap.

A standard top-loadmachineworks verywell.You should be able to findoneusedforverylittlemoney.Thewashingmachineshouldbelocatedoutsideofthegreenhousebutasneartothedoorsaspossible.OursislocatednexttotheGerminationChamber.

ChestFreezer

Achestfreezerisoptionalbutveryuseful.Weuseoursprimarilytostorefrozenfish. It can be locatedwherever is appropriate for you.Ours is located on theopposite side of the cooler from the Germination Chamber and washingmachine.

HotWaterSystemHot water in the greenhouse is optional but may be required for a food andsafetypermit.Thetwooptionsareatraditionalhotwatertankoranondemandsystem. Ondemand typically operates on propane—we recommend it ratherthanatank.

StainlessSteelCounter/SinkForavarietyoftasks,fromwashinghandsandplantstocleaningfish,youwillneed a work area that is designed to get wet and is easy to keep clean andsterilize.Anall-stainlesscounterwithabuilt-insink is thebestoptionand theonlyonewerecommend.Wepurchasedoursusedforafractionofthepriceofanewunit.

Ourcounterandsink.

The sinkwill need to drain per your local building code. The sink cannotdrain into theWaste Tanks as you will be using sanitizers, bleach, soap andwaterqualitytestingchemicals.

ConstructingtheWashDownSinkThewashdownsinkiswhereyouwillwashtheCFBfiltersscreens2or3timesperweek.Tocapture thesolidsforfermentation,buildasimplevesselofyourowndesignthatdrainsintotheprimaryWasteTank.

FeedStorageCommercial fish feed typicallycomes in20kgbags,andstoragemustbedry,vermin-proofandascoolaspossible.The storagedoesnotneed tobeclimatecontrolledunlessyouarebuyingmorethana12-monthsupply,whichwedonotrecommend, and it does not need to be fancy. We built our feed storagecontaineroutofscraplumberandplywoodonapallet,insulatedtheinsidewith

sheetsofstyrofoamandwaterproofeditwithafewcoatsofwhiteexteriorpaint.

Ourwashdownsink,constructedofplywoodandcoatedwithliquidrubber,plumbedintotheWasteTank.

Ourfeedstoragecontainer.

Freshlycleanedfish.Notethehealthypinkcolor.

Ourtwo-sidedtroughsinfullproduction.

Adrianharvestinganothergreatcrop.

Ourfarmatsunrise.

Youngromaineenjoyingthebreezethroughtheroll-upside.

Truewatercress,NasturtiumOfficinale.

Tropicanagreenleaflettuce,justafterspacing/thinning.

Breenredromainelettuce.

Alkindusredbutterlettuce.

Fulltroughsshowingmultiplestagesofplantgrowth.

Freshlyharvestedwatercress(left),cutwithrootsforbulksales(center),andcutforsaladmix(right).

Romainehearts.

HarvestedGiantRedmustard(left)andAbundancebabykale(right).

Freshlymadesaladmix.

Layoutoffishtanks,TankManifold,RFSandCFB.

Maturerainbowtroutraisedonourfarm.

FingerlingwithBacterialColdWaterDisease.Notetheskinlesionanderodedfins.

Substratesfromlefttoright:looserockwool,Pro-Mix,expandedclaypebbles,cococoir.

C

ManagingtheEcosystem

HAPTERS 1–5 INTRODUCE all the major components and concepts of anaquaponicfarmandteachyouhowtobuildourdesign.Chapters6–11will

discussthemajorsubsystems(aquacultureandhydroponics)andteachyouhowtorunthefarm.

Inthischapter,wediscusstheprimaryjobofanaquaponicfarmer:managingtheecosystemyouhavecreated.Inparticular,wewilldiscusshowbacteriaarethevitallinkbetweenfishandplants.

BacteriaMostpeopleunderstandthataquaponicfarmingmeansraisingfishandgrowingplants. While this is true, we encourage you to think of yourself first as abacteria farmer. The much-vaunted relationship between plant and fish isactually a three-way symbiosiswith bacteria as the vitalmiddle link.Withoutvigorousbacterialcolonies,noamountofworkwillpermitthefishandplantstosurvive,letalonethrive.

Theroleofbacteriainanaquaponicsystemistoremoveordecomposethemetabolicwastes produced by raising fish. This is called biofiltration.Wastesinclude ammonia, which is excreted from fish gills and is also found in fishurine, fish feces and any uneaten fish feed. Removal and decomposition ofwastes from the system is critical.Ammonia quickly becomes toxic to fish atlevels greater than 3 ppm, and high levels of organic particulates can also bedetrimentaltofishhealth.

Oxidationofammoniabybacteriaiscallednitrification.Thedecompositionof organic particulates into their elemental constituents by bacteria is calledmineralization. The bacteria colonies of an aquaponic system are called thebiofilter.

NitrifyingBacteriaThejobofnitrifyingbacteriaistoconvertammoniaintonitratesthroughatwo-step oxidation process accomplished by two families of nitrifying, bacteria:ammonia oxidizing bacteria which oxidize ammonia into nitrites, and nitriteoxidizing bacteriawhich oxidize nitrites into nitrates. There aremany speciesand strains of bacteria within each family. In an aquaponic ecosystem, theprimaryammoniaoxidizingbacteria are thoseof thegenusNitrosomonas, andtheprimarynitriteoxidizingbacteriaarethoseofthegenusNitrobacter.

Nitrates are a bioavailable form of nitrogen which is the most importantmineralelementforthegrowthofplants,particularlyintheleafyvegetablesyouwill be growing.When the biofilter is robust and operational, the two stageshappenalmostsimultaneously,whichistosaythatthenitrites,oncecreated,areveryrapidlyconverted intonitrates.Ahigh levelofammonia(>2ppm)and/ornitrites(>1ppm)isanindicationofaproblemwiththebiofilter.

Nitrifyingbacteria are autotrophic: theyderive their energy from inorganiccompounds,primarilyammoniaandCO2 inanaquaponicsystem.Thebacteriainvolvedinthisprocessbuildstaticcoloniescalledbiofilmsthatgrowonalltheunderwatersurfaces.Biofilmsareslimyfilmsthatcoatalldarkandwell-aeratedunderwater surfaces. They are obligate aerobes (they require oxygen to grow)and are relatively non-mobile, tending to colonize an area and stay there.Nitrifyingbacteriaareslowertoreproducethanmineralizingbacteriaandcanbequickly out-competed for space and oxygen in the presence of high levels oforganicparticulates.

MineralizingBacteriaThejobofmineralizingbacteriaistoconvertthesuspendedorganicparticlesinthe system into other essential minerals vital for plant health. Mineralizingbacteria are heterotrophic: they derive their energy from organic compounds,primarilyfecesandexcessfeedinanaquaponicsystem.Theyarealargefamily

of thousands of different species. Unlike nitrifying bacteria which createimmobile colonies, mineralizing bacteria float freely throughout the system,colonizinganddecomposingsuspendedsolids.Mineralizingbacteria reproducemuch more rapidly than nitrifying bacteria. As mineralizing bacteria can beaerobicoranaerobic,themineralizationprocessoccursinallareasofthesystemwhere solids accumulate, even in areasof lowoxygen, such as theRFS, filterscreensandtankdrains.

BacteriaandUVBoth classes of bacteria are killed by the UV levels we recommend. Fornitrifyingbacteriawhicharemostlystatic,thisisnotaproblemasonlyoutliersto the colonies pass through the UV units. For mineralizing bacteria whichreproduce rapidly, the UV sterilizers help to keep the population at anappropriatelevel.

MineralandNutrientContentAmmonia,NitritesandNitratesAmmonia, nitrites and nitrates are all forms of nitrogen.Ammonia is toxic tofishatshort-termconcentrationsof>3ppmandlong-termconcentrationsof>1ppm.Nitritesarehighly toxic to fishatconcentrationsof>1ppm.Nitratesarefar less toxic to fish and canbe tolerated at concentrationsup to~1,000ppm,althoughundernormalconditions,theplantswillkeepnitratesbelow500ppm.

Plants can tolerate higher concentrations of ammonia and nitrites than fishand can tolerate very high concentrations of nitrates (> 2,500 ppm), thoughbeyond a certain point they are redundant. Nitrates are the primary source ofnitrogen for plant growth, so the plants will suffer from nutrient deficiencieswhennitrateconcentrationsarelowerthan100ppmforprolongedperiods.Thesensitivityof the fish tonitrates is the limiting factorwhen it comes tonitrateconcentrations.

IMPORTANT

Thekeytolerancesforoursystemare:ammonialessthan3ppm,nitriteslessthan1ppmandnitratesbetween100–1,000ppm.

OtherPlantNutrientsThe crucial elements for plant growth are nitrogen (N), phosphorous (P),potassium (K), calcium (Ca),magnesium (Mg) and iron (Fe).N, P andK aretypically considered macronutrients and all others micronutrients. In anaquaponic system that grows only leafy (non-fruiting) plants and that mustsustain bacterial colonies, the vital nutrients are N, K, Ca, Mg and Fe.Phosphorous, though present in small amounts, is not needed in the largequantitiesrequiredforfruitingplants.

Theprimary input into the system is fish feed. It is theoriginofallof thenitratesand themajorityofminerals.Fishconsume the feed,excreteammoniathrough gills and urine, produce large amounts of feces and leave some feeduneaten. The ammonia is converted into nitrates via a two-step oxidationnitrificationprocesswhichistheprimarysourceofnitrogenfortheplants.Thefeces and excess feed, converted into their elemental constituents viamineralization,arethesourceofmostothermineralsandnutrients.

Although the feed contains everything needed by the fish, it tends to bedeficientinCa,K,FeandoccasionallyMg.Foridealplantandbacteriagrowth,theseelementsmustbesupplementedtokeepthemineralcontentbalanced.

CaandKaresupplementedwhenaddedtothesysteminhydroxideformtomanagepH(seebelow).Hydroxidesareveryalkaline,thusaddingtheminthismanner has the double benefit of raising the pH and supplementing deficientminerals.

Fe andMg don’t affect pH and tend to be less deficient inmost systems,dependingonthewatersource.Theyaresupplementedlessfrequentlybyaddingasmallamount(approximately1ppm)ofEpsomsalts(magnesiumsulfate)and

2ppmofchelatedironaboutevery2–3weeks.

IMPORTANT

Onlysupplementwithahigh-qualitychelatediron.Neverinputrawironoranyironthatcanrust.Ironoxide(rust)istoxictoallorganismsinthesystem.

Themineralcontentinyoursourcewaterwillaffectthebalanceofmineralsinthesystemandcanvarygreatlydependingonthesource.Regularlytestyourwatersourceandadjustaccordingly.

Thebalanceandconcentrationsofallmineralsandnutrientsaremonitoredthrough regular testingwith a chemical testing kit and regular observations oftheplants.

ChemicalTestingChemicaltestsuseachemicalreaction(titration)tomeasuretheconcentrationofspecific elements in awater sample. They do not rely on electronics, and theonlypotentialforincorrectmeasurementishumanerror.Weusechemicaltestsonaweeklybasistoassessammonia,nitrites,nitrates,potassium,calcium,ironand,optionally,phosphorus.Duringtheinitialcycling,orstartupphase,youwillbetestingoften(uptotwiceperday).Asyoursystemstabilizesandyoubecomefamiliarwithitstendencies,testingfrequencydecreasestoonceortwiceaweek.

AsdiscussedinChapter5, testingisdonewithacombinationofthreekits.WeuseanAPIFreshwaterMasterTestKittotestammonia,nitrites,nitratesandpH,andtoconfirmtheaccuracyofthepHcontroller.WeuseaNutrafinA7860MasterTestKit totestforhardness,calcium,phosphorusandiron.WetestforpotassiumwithaLamotte3138-01PotassiumKit.

TestpHweeklywithachemicaltesttoconfirmthatthedigitalpHcontrolleris accurate. All digital controllers require regular calibration and even whenregularly calibrated can read incorrectly. Chemical pH tests are more reliable

than digital meters as long as the tests are not past their shelf life and theoperatorcarriesouttheinstructionscorrectly.WhencalibratingapHcontroller,usehigh-qualitycalibrationsolutions.WerecommendBluelab4.0and7.0.

Theprocedureforusingachemicaltestkitvariesfromkittokit.Followtheinstructionsprecisely.

SampleWaterLocationThe location from which sample water is taken for testing is important asdifferentareasofthesystemwillshowdifferentresults.Forexample,iftestingammonia for biofilter performance, collect the sample from one of the inletspouts (immediatelybefore the fish tanks).Theprimary sourceof ammonia isthefish,so this locationwillhave the lowestammonia,as thebiofilterhas themosttimetooxidizeit.Ammoniashouldnotbepresentinhighconcentrationsataninletspoutifthebiofilterisfunctioningproperly.Conversely,ifatestsampleistakenfromtheTankManifold(immediatelyafterthefishtanks),thetestwillshowelevatedlevelsofammoniawhichmayincorrectlybeinterpretedasasignof poor biofilter performance, when in fact the sample water hasn’t yet beentreatedbythebiofilter.

IMPORTANT

Allsamplesforfishwaterqualitytestingarecollectedfromthetankinletspouts.Allsamplesforplantwaterqualitytestingarecollectedfromthetroughinlets.

It isalsopossibletoestimatetheefficacyofeachcomponentinthesystembycollectingsamplesatboththeinletandoutletofacomponentandcalculatingthe difference between them. For example, to determine the concentration ofammoniathefishareproducingatagiventime,collectwatersamplesatatankinletspoutandatthetank’sSPAoutlet.Iftheinletsampletestsat0.25ppmandtheoutlettestsat2ppm,wecanestimatethatthefishareproducingaround1.75

ppmof ammonia at the time the testwas taken.Using this samemethod, it ispossible toestimate thenitrificationrateof thebiofilter, thedenitrificationrateofthehydroponicsubsystemandtheoxygenconsumptionineachfishtank.

PlantObservationIn all types of farming, being proficient at gauging plant health via directobservationiscrucial.Overtime,youwillbecomeanexpertatidentifyingbugand pathogen issues, mold and mildew, and nutrient deficiencies before theybecomeaseriousproblem.Dailyobservationandearlyremovalortreatmentisthenumberone tool in thegreenhouse and the first lineofdefense against allproblems.

Everydaywhenyouarriveatthegreenhouse,walkthroughthetroughsandobserveyourplants.Thisshouldonlytakeafewminutes.Onaweeklybasis,doa more in-depth plant evaluation where you look at each plant for problemsymptoms.

Does anything look different from yesterday? Do you see any problemsymptoms, such as odd discoloration in the leaves, unusual or unexpectedgrowthpatterns,pestsorsignsofpests,oranymoldormildew?

We cover this subject and remedies in Chapter 10. The key point is thatcertain signs, particularly leaf discoloration, are indicators of a lack of one ormorenutrients.Regardlessofwhatthechemicalteststellyou,theplantsarethetrue arbiters of themineral quality of thewater. If the plants are healthy androbustandgrowingrapidly,strivetomaintainthemineralcontentasitis.Iftheplantsshowdeficiencies,discernwhatismissingandpromptlysupplement.

NutrientRecyclingIfyouopttoproduceyourownbiodigestedfertilizer,onebenefitisthatitcanbeaddedbackintothesystemtosupplementmineralsandboosttheoverallnutrientcontent. The fertilizer created in the biodigestion process contains numerousminerals that eitherweren’t previously bioavailable to the plants orwere onlypresentinlowerconcentrations.Byaddingyourownfertilizerbackintotheverysystemthatcreatedthestartingmaterial,youcan“closetheloop”byrecyclingwhatwaspreviouslyawastematerialand, in theprocess,createanevenmoresustainableaquaponicfarm.

Theamountstorecyclewillvarygreatly,basedontheconcentrationofyourfertilizer and its primary constituents. Lab test the fertilizer to evaluate howmuch isappropriate.The testing isalsoveryhelpful,perhapsevenmandatory,forsellingit.Asaroughreference,werecycleapproximately8literseveryweekbackintooursystem.Theonlylimitingfactor tohowmuchcanberecycledistherequirementsforfishwaterquality.Aslongasthereisnoammoniapresentin the fertilizer and it is well aerated, you should have no problems. Whenrecyclingfertilizerbackintothesystem,divideitevenlyintothetroughinlets.

WaterQualityandManagementFish, plants and bacteria (nitrifying andmineralizing) all have different waterquality preferences. The objective is to strike a balance between therequirementsofeachwhilemaintaininganenvironmentthatcanbetoleratedbythe individual organisms. As the goal of a commercial aquaponic farm is togenerate revenue fromplants, and to a lesserdegree fish, thebalancebetweenthe conditional requirements is heavilyweighted in favor of the elements thatactually generate revenue. The essential qualities to manage are pH, watertemperature,dissolvedoxygen,nitritesandnitrates,andmineralcontent.

pHSource water will vary in pH. In general, municipal source water will bebetween6.5and7.5.Wellwaterwillvarydramaticallydependingon the localgeologyandmayfluctuateseasonally.Waterunder6.0isextremelyacidicandover8.0isextremelyalkaline.Avoidusingsourcewaterthatiseitherextreme.

Duetothecontinuousbacterialprocessesofnitrificationandmineralization,thepHofanaquaponicsystemwilltypicallyslowlyacidify.Withoutcorrection,the systemwill eventually become too acidic for fish andbacteria.Plantswillalso suffer from nutrient deficiencies if the pH is too low or too high for anextendedperiod.

EachorganismprefersadifferentwaterpH.Fish ingeneralpreferapHof7.0orhigher,thoughcertainspecies,includingtrout,willtolerateandstillthrivein slightly acidicwater. Plants on the other hand require acidicwater to fullyutilize thewide variety ofminerals needed for growth.Both types of bacteria

also prefer a pH of 7.0 or higher, and as the pH drops, their growth andperformanceincreasinglysuffer.

WhenconsideringthedifferentpHpreferences,weprioritizetheneedsoftheplants as long as the fish can still thrive and the bacteria can perform well.Dependingonthequalityoffeedusedandthepriceperpoundforharvestedfish,you will more or less break even on raising fish. Plants generate the vastmajorityofaquaponic income,andthemorerobustandrapid theirgrowth, themoreincome.

IMPORTANT

OursystemisdesignedtooperateatapHof6.5,+/-0.1.ThispHisidealforleafygreenplants,iswelltoleratedbytrout,andwhileoutsidetheoptimumrangeforbothtypesofbacteria,theystillgrowandperformmorethanwellenoughtoservetheirfunctions.

TwopHManagementMethods:BufferingvsHydroxidesThere are two primary methods of pH management in an aquaponic system:“buffering”thepHor“adjusting”thepH.

“Buffering”referstowater’sabilitytoresistachangeinpHasacidisadded(by the bacterial processes in aquaponics). Buffering uses calcium carbonate,usually in the form of crushed oysters or eggshells, to increase the bufferingcapacityofthewater.Inpractice,carbonateswillkeepwateratafairlystablepHof 7.0–7.5 even if excess carbonates are added. This method is forgiving ofmistakesasexcessdissolvedcarbonateswillprecipitateoutofsolutionuntilthecarbonate level in the water drops to the point at which the precipitatedcarbonatesbegintoslowlyredissolve,thuscontinuingtobufferthewater.Whenusing thebufferingmethod,supplementalpotassiumshouldbeaddedregularlyintheformofpotassiumsulfate(K2SO4),whichhasafairlyneutralpH.

TheprimarydrawbacktothebufferingmethodisthatthepHismaintainedat around 7.0–7.5 which is not ideal for plant growth. As we prioritize cropproduction,thisisnotsatisfactory.

Themethodof“adjusting”thepHusescalciumandpotassiuminhydroxideforms to incrementallyadjust, rather thanbuffer, thepH.Hydroxidesaremoresoluble in water than carbonates, and only very small amounts are needed tomake adjustments. Hydroxides are also used up rapidly in this method, soadjustmentsneedtobemaderegularly.Smallerandmorefrequentadjustmentsenableamuchmoreprecise levelofpHcontrol than is found in thebufferingmethod,andtheoperatorcankeepthepHinarangethatismoreidealforplantgrowth.Ifusingthismethod,theuseofbothcalciumhydroxideandpotassiumhydroxidewillhelptomaintainthedesiredequilibriumofthesemineralsinthewater.

IMPORTANT

Calciumandpotassiumhydroxidesareverycausticandshouldonlybehandledwhilewearingpersonalprotectiveequipment.

Thedrawbacktothehydroxidemethodisthatitislessforgivingofmistakes:iftoomuchofeitherhydroxideisadded,thepHwillspikerapidlyandpossiblykill both fish andbacteria, and if notmeasuredandadjusted regularly, thepHmayquicklyfalltoasimilarlytoxiclevel.

We recommend using the hydroxide method, including an automatedcontroller, to allow precise control of the pH. This enables far superior plantgrowth.

pHManagementYoursystemwilllikelyonlyrequirepHadjustmentupordown,mostlikelyup.MostpHcontrollerscanbesettoadjustupordownbutnotboth,whichisfine.Ifyoursourcewaterisparticularlyhard,typicallyduetoahighlevelofcalciumand/ormagnesium,youmayfindthatyoursystemnaturallyhasanidealpHof6.5withlittleornoadjustment,oryoumayevenfindthatyouhavetolowerthe

pH.Formostwater sources,youwill likelyonlyeverbeadjusting thepHup.Testyour incomingsourcewaterbefore itenters thesystem.Initially,youwilldothisregularly.Asyoulearnyoursystem,thiscanbemuchlessfrequent.

Calcium and potassium must always be relatively equal in concentrationwithin the system as they have a direct competitive relationship within asolution. Ifoneof theseelements ispresentatasignificantlyhigher level thanthe other, the element of lower concentration will become insoluble andprecipitateoutofthesolution,thusbecomingunavailableforplantuptake.Thistypically only occurs in extreme cases, but to lower the risk, calcium andpotassiumareaddedinrelativelyequalamounts.Testforconcentrationsofeachonaregularbasis.

Calcium hydroxide is most commonly available in powder form andpotassiumhydroxideas a liquid, so theymustbeadded to the system throughseparatemeans.PotassiumisdosedviathepHcontrollerandcalciumviaasockintheCFB.

ThepHcontrollerprobe is locatednear thepump intake in thesump.Thisteststhewaterafterbeingmixedinthesumpandbeforeitentersthetanks.ThepH dosing tube inputs at the opposite (east) end of the sump, near the waterreturnfromthehydroponicsubsystem,toallowpropermixingbeforethewaterreaches the probe. The goal of inputting potassium hydroxide via the pHcontroller is tomaintain aminimum pH of 6.5. Potassium hydroxidemust bepure,meaning the liquid contains only potassiumhydroxide andwater.ChecktheMSDStoconfirm.WeuseAdvancedNutrientspHUp.

Calcium hydroxide, also known as hydrated lime or agricultural lime, isalmostneverpureandtypicallycontainssomemagnesiumoxideswhicharealsobeneficialforplants.AlwayschecktheMSDStoensureitdoesnotcontainanyadditivesoranti-cakingagents.

Put2–3cupsofthecalciumhydroxideintoasturdyfabricbagorsock,sealthesockandplace it in thedownstream(south)endof theCFB.Everysecondday,simplygivethesockaquickshake.Thoughimprecise,wehavefoundittobe the simplest and most consistent method of supplementing calcium in thesystem. Avoid shaking the sock too vigorously or you may add too muchcalciumandraisethepHhigherthanintended.

When first starting, do a chemical test for pH, calciumandpotassium4–6

hours after each sock shake.Asyouuse thismethod andwitness its effect onpH, you will quickly learn what is best for your system, and it will becomesecond nature. The objective from amineral standpoint is to keep at least 40ppmofbothpotassiumandcalciuminthesystem.

ThepHcontrollerwillceasedosingfora timeaftereachsockshakeasthepHrises.ThejobofthecontrolleristosimplymaintaintheminimumpHatalltimes.

IfpHdownisrequired,thereareseveraloptions,butwesuggestphosphoricacid(H3PO4),asthiswillalsoaddphosphorustoyoursystem.ChecktheMSDStoconfirmpurity.WesuggestAdvancedNutrientspHDown.

Ifyoursourcewaterishardduetohighcalciumlevels,youwillneedtoaddpotassiumtokeepthetworeasonablybalanced.Werecommendsupplementingwithpotassiumsulfate(K2SO4).

OnceyouhavelearnedwhatyoursystemrequiresforpHmanagement,ifthepH becomes unstable (swingingmore than 0.5 regularly), something is likelywrongwithinyoursystem.Likelycausesincludeadeadfishinthesystemoraprocessyouhaveoverlooked.Immediatelydoafullbatchofchemicaltestsandstopfeedingthefishuntilyoudiscerntheproblem.Fishcansurviveforweekswithoutfood.Afterapproximately24hours,theygointoareducedenergystatein which their metabolic processes greatly decrease, they consume very littleoxygenandproducelittletonoammonia.Inmostcases,youshouldbeabletodiscernandresolvetheproblemwithin24hours.

WaterTemperatureOur system is a cold-water design, most appropriate for temperate or colderclimates. This is verywell-suited tomany types of plant and certain types offish.Itislesswell-suitedtobothtypesofbacteria.

Many plants thrive in water that is 10–20°C (50–68°F), primarily leafygreenssuchaslettuce,kale,chard, thechoifamily,mustard,andherbssuchasmintandwatercress.Someplants thatyoumightassumewouldthrive,suchasspinach,growpoorly inaDWCsystem,as theydonot likehaving their rootssubmerged in water. Most fruiting plants are not well-suited, as cold-wateraquaponicsystemsaretypicallyabundant innitrogenbutrelativelydeficient inthephosphorousrequiredforfruitsandflowers.

Cold-water fish have a narrower preferred temperature range of 12–17°C(54–63°F).Water above 17°Cwill dramatically slow growth and increase therisk of infection and disease.Warmerwater also has a lower oxygen carryingcapacity.

Bacteriaarethecrucialentitiesindeterminingwatertemperature.Bothtypespreferwarmerwaterofat least20°C.Below20°C,growthandperformanceofthebacteriaprogressivelydrops.Theoptimumtemperature is thereforeashighasthefishcantolerateinordertominimizethelossofgrowthandperformanceofthebacteria.

IMPORTANT

TheRCAsystemisdesignedtooperateat16°C(61°F),+/-1°C.

DissolvedOxygen(DO)The amount of oxygen that can be dissolved in water is dependent on thetemperature: colder water is able to hold more DO than warmer water. Themaximumamount of oxygen that can be dissolved inwater at 15°C (59°F) isabout 10 ppm; at 25°C (77°F) it is only 8 ppm.This is amajor advantage ofcold-water aquaponics versus warm-water, which typically operates at around25°C.Theaeratorsusedinourdesignkeepthewatersaturatedatalltimes.

Theentitieswhichhavethemostneedofoxygenarethefish.Troutrequireatleast5ppmtosurviveand7–9ppmtothrive.DOconcentrationsbelow5ppmwill quickly suffocate trout. Plants also need continuous high levels ofDO tothrive, althoughboth theplants andbacteria can survive for short durations atconcentrations as low as 1 ppm. All entities in the system thrive with higherconcentrationsofoxygen,thuswesupplythemaximumpossible.

As fish need the highest levels ofDO, the objective is for thewater to befullysaturatedjustbeforeitentersthetanks.Forthefirstyearofoperation,test

DOeverydayortwo.AlwaystestDOascloseaspossibletothepumpintakeinthesumpandjustaftereachtankbyhangingtheprobedowntheSPAs.Thefirstmeasurement(inthesump)shouldalwaysread100%saturation(approximately10ppm).Thesecondmeasurement(intheSPA)shouldbenolowerthan4ppm.The difference between the two readings is the amount of oxygen the fishconsume.Ifthefirstreadingshowsfullsaturationbutthesecondislowerthan4ppm, either the fishbiomass in that tank is toohigh, thus they are consumingmoreoxygen than the systemprovides,or the systemflowrate is too lowandthusoxygenisnotbeingreplacedinthetanksquicklyenough.

Aftersometime,testingcanbecomelessandlessfrequent.WerarelytestforDO anymore except immediately after adding a new cohort and in thetransportationofcohorts.

OptimumWaterQualityParameters

“

CyclingtheSystem

CYCLING”ISTHEESTABLISHMENTOFTHEBIOFILTER(nitrifyingbacteria)and,inlargesystemslikethis,thegradualintroductionoffishandplants.Oncethe

systemisestablishedwitharobustandthrivingbiofilterandafullcomplementoffishcohortsandplants,youhavesuccessfullycycledyoursystem.

FillingtheSystemwithWaterBefore cycling the system, itwill need to be filledwith sourcewater.As thecyclingprocess isdone instages,at this timefillonlyTank1andone trough.Turn the valves off to Tanks 2& 3 and the other two troughs. Theywill bebroughtonlinewhenyouintroducethesecondandthirdcohorts.

Fillbothsidesofthetroughatthesametimetokeepthelinerfromshifting.Fill thesump,Tank1, theTankManifold,RFSandCFB.During thisprocess,check every visible connection for leaks and confirm all equipment functionsproperly.

Oncethesystemisfull(onetankandonetroughonly),turnonandtestbothpumps,bothaeratorsandtheUVsterilizers.

Ifthesourcewaterischlorinated,youwillneedtoletitcirculatefor24hourswithUVturnedontoremovethechlorinebeforebeginningthecyclingprocess.Whenyoulaterfillthesecondandthirdsetsoftankandtroughs,letthemsitfor24hoursbeforebringingthemonline.Onceonline,allowthesystemtocirculateforafewhourstomixbeforeinputtingfish.

During the cycling process, the UV sterilizers are turned off until thebiofilterisestablished.Forthefirstcohortoffish,turnontwoofthefourunits.

Closetheflowtotheothertwounits.Addthethirdunitwhenthesecondcohortoffishisinput.Addthefourthunitwhenthethirdcohortisinput.

IMPORTANT

Twotothreeweeksbeforebeginningthecyclingprocess,begingerminatingthefirstbatchofseeds.Movethemtotheseedlingareaafteroneweekandstartnewbatchesweekly.Thereisnowayofknowingexactlyhowlongthecyclingprocesswilltake,butyoumusthaveseedlingsreadytoplantoncethebiofilterisgeneratingnitrates.Thegoalistohavematureseedlingsreadytotransplantintoatroughoncethenitrateconcentrationhasrisenabove50ppmandammonia/nitritelevelsarelow.Ifseedlingsoutgrowtheirtraysbeforethesystemisreadyforthemtobetransplanted,consideritpracticeandcompostthem.Asyouwillbeplantingonly¼ofonetroughinitially,onlyfivetraysofseedsshouldbeneededperweek.Youwillneedtofeedseedlingswithastore-boughtfertilizeruntilyoursystemwatercontainstherequiredminerals.SeeChapter9forinstructionsongerminationandseedlings.

CyclingtheSystemThisisit:themomentwhenyoustartcreatingalivingecosystem.Younowhavea fully functional systemof inanimateobjects (troughs, tanks, plumbing, etc.).Waterflowsinacompleteloopandisoxygensaturatedbytheaerator.It’stimetocyclethesystemintolife.

The first step is to start establishing the biofilter by adding a source ofammonia and introducing nitrifying bacteria. The second step is testingwaterqualitytochartthegrowthofthebiofilterandconfirmitisfunctioning.Thefinalstep is the introductionof fishandplants instagesover9–12monthsuntil thesystemisatfullcapacity.

Ammoniaistheenergysourcefornitrifyingbacteriaandatthispointistheonly elementmissing. The first decision is to choose a source of ammonia toinput.There are twooptions: addpure ammoniadirectly into thewaterorusefishtogenerateammonia.Westronglyrecommendaddingpureammonia.Thisallowsprecisecontrolofammonialevelsandfasterstartuptimesashigherlevelsare possible. Using fish to generate ammonia at this stage has two major

problems: the fish are very likely to suffer or die, and the ammonia levelsproduced are not directly controllable by you. For reasons of both ethics andefficiency, using fish initially does not make sense unless a pure source ofammoniaisnotreadilyavailable.

IMPORTANT

Donotrushthisprocess.Thebiofiltergrowsslowly,andintroducingfishtoosoonwillcauseammoniaspikesandfailures.Welearnedthislessonthehardway.

Ifitisnecessarytocyclethesystemwithfish,usefeedergoldfishfromthepet store and consider them sacrificial. You should only need 0.5–1 kg ofgoldfish.Usesmallamountsoffeedinitiallyuntilyouhaveanideaofhowmuchammoniatheyareproducing.

IMPORTANT

Whenaddingammoniadirectly,itismandatorytouseonlypureammonia.Manycommonbrandscontainfillersorotherchemicals,suchasperfumes,foamingagentsoradditives.Asaruleofthumb,iftheproductisscented,foamswhenshakenorisnotclear,donotuseit.AlwaysrefertotheMSDStoensurethattheproductcontainsnothingbutpureammoniaandwater.

There are two options for establishing the biofilter: seed the system withstore-boughtbacteriaculturesorallowthebacteria thatarenaturallypresent intheenvironment tocreatecolonies.Thepotentialadvantage to the latter is thatthebacteriawillbemorelocallyadapted.Thedisadvantageisthatitwilllikelytake weeks longer than seeding the system.Without seeding, establishing thebiofilterwilllikelytake1–2months;withseeding,itmayonlytake2–3weeks.

Ifyouuseaseedbacteria,itmustbeapprovedforuseinfoodfishsystems.WeusedandrecommendProlineNitrifyingBacteria.

Don’taddammoniaorseedbacteriayet.

IMPORTANT

TheUVunitsmustbeturnedoffforthedurationofthebiofilterestablishment.

Take baseline measurements of ammonia, nitrites, nitrates, calcium andhardness.Record theconcentrationsofeachelement ina logbook.Ammonia,nitriteandnitratelevelsshouldallbe0ppm,calciumabove40ppm,andthepHshouldbebetween6.5and8.0.IfeithercalciumorthepHistoolow,increasebymixingsmallamountsofcalciumhydroxideintothesump.IfthepHistoohigh,lowerbymixingsmallamountsofphosphoricacidintothesump.Aftermixingadditions into the sump, wait for the additions to mix in the system beforeretesting.

Slowlyadd2–3ppmofammoniatothesystem,adding1ppmatatimeandtesting to confirm the concentration. To determine how much ammonia willequate to 1 ppm, take the total volume ofwater, then calculate theweight ofammoniarequired.1ppmisequalto1milligramperliter.FortheRCAsystem,the total volume of water is approximately 66 cubic meters (66,000 liters);therefore,1ppmequalsroughly66gofammoniainafullsystem.

Once you have sourced the ammonia, add 66g to the system. If yourammonia is in liquid form, itmaycontainwater, soyouwillneed tocalculatetheequivalentof66g (e.g., a50%water/ammoniasolutionwill requireadding132g total). In order to mix throughout the system more rapidly, add theammoniaatnumerouslocations.

Afterseveralhours, testand log theammonia level. Ifyourbaselinewas0ppmandisnow1ppm,you’veaddedtheperfectamount.Ifnot,adjustthedose

accordingly.Continuetoaddammoniainthismanneruntilaconcentrationof2–3 ppm is reached. If toomuch ammonia is added (> 3 ppm), replace systemwater with source water until the level is less than 3 ppm. (If you are usinggoldfishinsteadofaddingammoniadirectly,feedthemsmallamountsandtesttheammonia leveloften.Aimfora targetammoniaconcentrationof1–2ppm.Thismaytakeadayortwotoachieve.)

Waitseveralhoursandtesttheammonialevelagain,thenseveralmorehoursandtestagain.Oncethelevelhasstabilizedbetween2–3ppm,pourin4litersofProlineNitrifyingBacteriainthemostupstream(north)endoftheCFB.Ifyouareallowingthenaturallyoccurringnitrifyingbacteriatocolonizethesystem,allyou have to do is wait. Wherever ammonia is present, ammonia oxidizingbacteriawillsoonbefound.

The objective now is to continuously feed the bacteria the ammonia theyrequire to exponentially multiply.Maintain an ammonia concentration of 1–2ppmatalltimes.Twiceperday,testforammonia,nitrites,nitrates,calciumandpH.Createachartfortheseteststogaugeprogressovertime.Ifcalciumlevelsdropbelow40ppmorthepHdropsbelow6.5,increasewithsmalladditionsofcalciumhydroxide.Youdonotneedtoaddpotassiumatthisstage.

Thefirstindicationofbiofilterestablishmentisadropinammoniaandrisein nitrites as the nitrifying bacteria start the first stage of oxidation. Whenammonialevelsdropbelow1ppm,add1mgofammoniaforeveryliterofwaterinthesystem.AlwaysaddammoniainvariouslocationstogiveitampletimetomixpriortoreachingtheprimarybacteriacoloniesintheCFB.Theobjectiveistokeeptheammoniabetween1–2ppmuntilthebiofilterisfullyestablished.

Itmay takeoneweekormore to see thedrop inammoniaand increase innitrites.Continueaddingammoniaasneededandtesting/chartingtwicedaily.

Thenext indicationof successful cycling is a slowdecrease innitrites andincreaseinnitratesasthenitrifyingbacteriaconvertnitritesintonitratesduringthe second stage of oxidation. Continue adding ammonia and testing/chartingtwicedaily.Addcalciumasneededtokeepabove40ppmatalltimes.

The final indication is a radical drop in both ammonia and nitrites and aconsistentlyhighlevelofnitratesasthebacteriabecomeestablishedsufficientlyto convert ammonia rapidly to nitrites and then almost instantly to nitrates.Continueaddingammoniaandtesting/chartingtwicedailyforatleastoneweekto confirm that the biofilter is stable and successfully converting ammonia tonitrates rapidly.At thispoint, you shouldbe reading~1ppmof ammonia and<0.25ppmofnitriteswhenmeasuringatthesump.

You have now established the biofilter. Continue adding ammonia to feedthebiofilteruntilammoniaadditionsarereplacedbythefirstcohortoffish.

Inasmallersystem,thenextstepwouldbetoaddfishandplantsuptothesystem’s capacity. In a systemof this sizewithmultiple fish cohorts, fish andplants are added gradually. It takes up to a year to bring the system to 100%capacity(assumingnomajorproblems).

TheImportanceofCalciuminCyclingOur sourcewater is very soft and lacks calciumbecause it does not percolatethroughlimestoneonitsjourneyintothelocalaquifer.Whenwefirstcycledoursystem, we were unaware of the vital importance of calcium in the cyclingprocess.Weaddedammoniaandseedbacteria,testedandcharted,andsawtheexpected indicators. Sadly, we proceeded to add the first fish cohort and lostthemwhen the bacteria ran out of calcium and crashed, leading to amassivespikeinammonia.

Calcium is a necessary element for bacteria to function. If your watercontains less than 40 ppm, supplementing is required before seed bacteria isadded.

Werecommendusingcalciumhydroxide.UsewithcautiontoavoidraisingthepHtoohigh.ItisimportanttokeepthepHbelow8.0andideallybelow7.0duringthecyclingprocess.DifferentbacteriathriveatdifferentpHlevels.Yoursystemwillbeoperatingat6.5,soyouwanttoestablishbacteriathatwillthriveatthatpH.

TheFirstCohortofFishStartwithahalfcohortoffishinitiallysoasnottooverwhelmthebiofilter.FortheRCAsystemasperthecalculationsinChapter3,thismeansapproximately125fishthatweigh10–20geachforatotalinitialbiomassof1.25–2.5kg.Thesecondandthirdcohortscanbefullcohorts.

A few days before adding the fish, stop adding ammonia andwait for theconcentrationtodropbelow1ppmbeforeintroducingthem.Youshouldneverhavetoaddammoniatothesystemagainasthefishwillnowcreateitnaturally.

TurnontwooftheUVsterilizers.TheUVunitswillnowalwaysberunningduringnormaloperation.

For the first2–3daysafter introducing the first cohort,giveonly¼of thecalculateddailyfeed.Increasetheamountgraduallyover1–2weekstoreachfulldaily feed rate. Repeat this process for all future cohorts. See Chapter 8 fordetailsonintroducingnewcohortsandcalculatingthedailyfeedrate.

ContinuetestingandchartingwaterqualityandpHdaily,collectingsamplesfromatankinletspout.Itisveryimportantoncefishareinthesystemthattheammonia level does not exceed 3 ppm and nitrites 1 ppm. If your biofilter is

growing quickly, this will not be a problem. If you see results at or close toeitherof theselevels, immediatelystopfeedingthefishuntil thelevelsreduce,thengraduallyre-introducefeed.

TheFirstYearofOperationSince before the start of the cycling process, you have been germinating fivetrays per week, so you should now have large healthy seedlings, ready fortransplant. Allow the nitrate concentration to rise above 50 ppm beforetransplanting the first seedlings. At this time, begin supplementing iron andmagnesium(seeChapter6).Atthispoint,thepHcontrollershouldbeonlineandyoushouldbeshakingthecalciumsockgentlyandinfrequently.

During the first fourmonthsofoperation,youwillhaveonlyahalfcohort(125fish).Oncenitratesareabove50ppm,plant¼ofthefirsttrough(22rafts)with the largest, healthiest seedlings. Replant the first¼ troughwhenever thecrop matures and is harvested. So long as there are no signs of nitrogendeficiency,plantanother¼of the troughonemonthafter the first (oneside isnowfullyplanted), thenaddthe third¼at thestartof the thirdmonthandthefourth¼at thestartof the fourthmonth.By the fourthmonth, the first troughshouldbefullatalltimes.

Forthefirstfourmonths,seedingfivetraysshouldprovideampleseedlings,thoughyoumay requiremoredependingon theproduction times. If youhaveexcess seedlings, consider it practice and plant only the largest and healthiest.Afterfourmonths,youshouldhaveonetroughfullyplantedatalltimes,andyouarenowreadyforthesecondcohort.

Prior to introducing the second cohort, fill Tank 2 and the second trough.Allowanychlorinetodissipateforatleast24hoursbeforebringingthesecondtank and trough online. Once online, let the system circulate for a few hourspriortoinputtingthesecondcohort.

Ifyouarerotatingcohortsbetweentanks,transferthefirstcohorttoTank2,sampling and counting the fish as youmove them (see Chapter 8). Input thesecond,fullcohort(250fish)andfollowthesame¼plantingprogressioninthesecondtrough,adding¼ofthetroughpermonth.Seedtentraysperweekfromnowon.Eightmonthsafterintroducingthefirstcohort,youshouldhavetwofulltroughsatalltimes.

Followthesamepatternforthethirdcohort(250fish)andtrough.Seed15traysperweekfromnowon.

Throughout the first year, continue testing and charting ammonia, nitrites,nitrates and pH daily to monitor the biofilter. As the biofilter matures andstabilizes, and you become familiar with your system, testing frequency candecrease toweekly. If theplantsshowsignsofnitratedeficiency,decrease theplanting progression speed or increase the daily feed rate. Test weekly forcalcium,potassiumandiron,andperformregularplanthealthobservations(seeChapter9).

FullCapacityOnce you have three cohorts (including the first half cohort) and three fulltroughs,youhavesuccessfullycycledyoursystemtofullcapacity.Thiswilltakeoneyear, assumingnomajorproblemsor lossesofcohorts.Nowa robustandsymbioticecosystem,yoursystemwillcontinue toestablish itselfandstabilizefor some time. When you harvest the first cohort, rotate the fish tanks andintroduce a full fourth cohort.You do not need to follow the samegradual¼trough planting progression again. At this point, you should be harvesting,transplanting and seeding at least 15 trays perweek (seeChapter 9). Strive tohavealltroughsfullatalltimes.

T

•••••

•

RaisingFish

FishSpeciesHEREARESEVERALPOTENTIALOPTIONSFORSPECIESOFFISHtoraiseinacold-water aquaponic system. The only mandatory characteristic is that they

growwellincoldwater(under18°C/64°F).Sincedayone,wehave raisedOncorhynchusmykiss, commonlyknownas

rainbowtrout,or just“trout” in thisbook.Otherspecies,notablysturgeonandcoho(salmon),mayalsobewell-suitedtocold-wateraquaponicsbuttodatewehavenotexperimentedwiththem,sowecannotspeakfromexperience.

Trout have numerous advantages that make them ideal for aquaponicproduction:

Fingerlingsareusuallyeasytosourceintemperateregions.Theytypicallyrequirelittlelicensingoroversightbygoverningbodies.Theyhaveanexcellentfeedconversionratio.Theyarewell-knownandalwaysindemand,thuseasytomarket.TheyaretolerantofthelowerpH(6.5)whichisrequiredforoptimumplantproduction.Their idealwater temperature is15–16°C(59–61°F),perfectforcold-wateraquaponics.

FeedConversionRatioFeedConversionRatioisthecapacityoffishtoconvertfeedintobodymass—

thelowertheratio,thebetter.Youmayreadthattrouthavearatioofaslowas1.1,whichmeansthatforevery1.1unitsoffoodweight,thefishwillgain1unitofbiomass.Inourexperience, thisholds trueonlyunderperfectconditions,soexpecttoseeaslightlyhigherratio.

FishSourcingYouwillmost likely be sourcing fish from an external source, as operating ahatcheryisacompletelyseparateprocessnotcoveredinthisbookandlikelynotsomethingyoushouldconsiderunlessyouareexperienced inaquaculture.Theeaseofaccessingafishsupplywilldependgreatlyuponyourlocation.

Seek a hatchery that is Certified Disease Free by your local fisheriesauthority and that can provide aCertificate of FishHealth for fingerlings youpurchase. Note that even Certified Disease Free hatcheries will occasionallyencounter diseaseproblems, but a goodhatcherywill remedy thesequickly astheyariseandproblems,shouldnotbeongoing.

Thesizeofthefishyouputintoyoursystemwilllargelybedeterminedbythe availability and cost of fingerlings in your area. The amount of time theyspendinthesystemisdeterminedbytheirgrowthrateandtargetharvestweight.

We sell almost all our fish to a local restaurant that requires them to beminimum1 kg.Accordingly,we source fingerlingswhich are typically 10–12cmlong,weigh10–20gandyieldaverage1kg(orlarger)fishin11–12months.If you want larger fish at harvest, you can either source larger fingerlings orleavetheminthesystemlonger.UsetheformulasinChapter3todeterminethecorrectnumberoffishandtheirexpectedgrowthrate.

Fish that are smaller than fingerlings are called “fry” and must be fed aspecialcrumblefeed.Wedonotrecommendthem.Fingerlingsareatleast3–4monthsoldandcaneatpelletfeed.

Alwaysinspectfishatthehatcheryor,ifdelivered,whentheyarrive.Checkfor weak or dead fish.Weak fish will often be floundering near the surface,lethargicand/orfloatingontheirsideorback.Checkalsoforanyobvioussignofdisease.Themostobviouswillbepatchydiscoloredskinorfrayedwhitefins.Transporting fishcanbe stressful to them, so it isnotunusual to seea fewofthemshowing signsofweakness/lethargy,but there shouldbenodead fish. If

therearesignsofdiseaseormorethanafewdeadfish,contactthesupplierandhavethemresolvetheproblemorfindanewsupplier.

Wepayapproximately$1.00perfingerling.

RecordKeepingEverycohortoffishgrowninthesystemmustbeaccompaniedbyitsownlogtotrackfishgrowthandhealth.Insomecases,thismayalsobealegalrequirementofhavinganaquaculturelicense.Assigneachcohortasequentialnumber.ThisnumberwillbeusedontheFishSampleLogandtheCohortLog.

Periodic samplingof eachcohort is recordedon theFishSampleLog, andthedataisusedtocalculatethebiomassofeachcohort.TheCohortLogisusedto track thegrowthof thecohortover time, aswell as thenumberof fishandtotalbiomass.Thedataisusedtocalculatethedailyfeedrateforeachtank,andtherateisrecordedontheDailyLog.SeeChapter11forsamplelogs.

IMPORTANT

ThetotalbiomassinthesystemiscalculatedbyaddingthetotalbiomassofeachtankasrecordedontheCohortLogs,inordertoensureyoursystemisoperatingwithinthetargetbiomassrangeasdeterminedinChapter3,andtodeterminewhentoharvestfishandhowmanyfishtoharvest.

FishTransportIfyouarepickingupfromasupplier,youwillneedalive-haulingsetupwithatank, oxygen supply and a DO meter. Live-hauling fish means building aportable life-support system. There are several considerations to take intoaccount, notably stocking density, temperature, DO level and water quality.During transport, the conditions must be kept at or better than the standardenvironmentalconditionsfortrout:15–17°C(59–63°F)andmorethan7ppmof

DOThestockingdensitycanbehigherthannormalaslongascareis takentopreventexcessiveammoniaorsolidsbuildupandtheDOlevelismaintained.

Ifyouarefollowingourdesign,youwillbeinputtingcohortsof250fishthatare between 10–20g each (2.5–5 kg biomass). A biomass of 5 kg couldpotentially be transported by car in a large cooler (> 50 L), but this does notleavemuchwiggleroomandcanbeundersizedifthefishareonthelargerendofthescale.

Werecommendhaulingbytruckandeitherbuyinganinsulatedfishtoteorbuilding a customhauling tank.We recommend the tank be at least 160L toaccommodateupto10kgbiomassfortransportthatisfourhoursorless.

Our tank is 3′×3′ by 1.5′ high, holds approximately 380L,weighs 380kg(840lbs)whenfullandwassizedtofitoursmallfarmtruck.Withthistank,wearecapableofhaulingamaximumof35kgoffishusingsupplementaloxygen.If you build a custom tank, it should be constructed out of ¾″ marine-gradeplywoodandwaterproofedwith2or3coatsofepoxyresin.SeeIMPORTANTnoteonEpoxyandFishSafetyinChapter4.

Thetankmustbewellconstructedandruggedenoughtohandletheforcesofcorneringandbrakingwhenloadedwithwater.Makesuretoincludeheavy-dutytie-downrings.

Thetankmusthaveawatertightlidandadrainvalveononeside.Constructthe lid tooverhang all four sides anduse a foamgasket to create awatertightseal.Installabulkheadfittinginthecenterofthelidwithastandpipethatrises6″.Whenhauling, run theoxygen lineandDOprobe through it.Youcanalsouseittotopupthetankifneeded.

Dissolved oxygen, temperature and time are the biggest considerations fortransport.DO isby far themost important.Once the fishare in the tank, theywillimmediatelybeginconsumingoxygen,andiftheyhavebeenfedinthepast24 hours, will also be producing ammonia. The longer the trip, the moreammonia buildup and oxygen consumption. These can be decreased bywithholding feed24–48hoursprior to transport, enabling longer tripsormorebiomasspertrip.

IMPORTANT

Forbiosecurity,alwayssterilizethehaulingtankpriortoandaftereverytransport.Useagermicidalcleanerandwashthetankoffsite,preferablyatacarwash.

Livehaulsetup:fishtransporttank,oxygentank,pressureregulator,flowmeterandmicro-bubblediffuser.

Unlessyou areusing an insulatedhauling tankormakingvery short trips,onlytransportfishwhenthetemperatureiscool.Duringthesummer,transportatnightorearlyinthemorning.

Oxygen supplementation is mandatory during transport, even for smalldistances.Fishwill consume theavailableoxygen surprisingly fast, if it isnotreplaced.Useaportableoxygentankspecificallyfortransport.Connectthetank

to a single SweetwaterMicroBubbleDiffuser via a flowmeter and regulatorinstalledthroughtheportinthetanklid.Tominimizestress,DOlevelsshouldbemaintainedat100–150%saturationduringtransport.

Bring your DOmeter with you for transport. If it is possible to have theprobe in the tank and the meter in the cab of the truck (running through awindow)thisisideal,asyoucanmonitoroxygenlevelsatalltimes.

Additionally, youcan add0.5%salt (5g salt per liter ofwater) to the tankbeforetransport.Thisservesasaprophylacticpathogentreatment,increasesfishtoleranceof ammoniaandnitrites andhelps to reduce stress.The saltmustbepuresodiumchloride(seeSaltBathTreatmentlaterthischapter).

IMPORTANT

Alwaysfillthehaulingtankcompletelyfullofwater,evenifonlyasmallnumberoffisharebeingtransported.Ifanairgapisleftatthetopofthetank,thewaterwillslosharoundviolently.This“freesurfaceeffect”willstressanddamagethefish,andmovementofwaterinthetankcandestabilizethevehicleenoughtocauseittorollover.Whenthetankisfulltothelidwithnoairgaps,theliquidmassbehavesasthoughitwasasolidandmaintainsastablecenterofgravitywhenthevehicleiscorneringorleaning.

FishTemperingandQuarantineRegardless of how fish arrive at your farm, follow these procedures fortempering and quarantine. Before receiving fish, make sure to fill the PurgeTankhalffullwithsystemwaterandturnonacirculationpumporsupplementaloxygentoprepareforquarantine.

TemperingAsaruleofthumb,fishshouldnotbeexposedtoatemperaturechangeofmorethan5°CorapHchangeof1.0ina20-minuteperiod.

Immediatelyuponarrival,testthehaulingtankwaterandyoursystemwater

fortemperatureandpH.Ifthereisadifferencebetweenthemofmorethan5°Cor1.0pH,youmust temper the fish in thehauling tankprior tomoving theminto quarantine in the Purge Tank. Add system water to the hauling tank,exchangingnomorethan10%ofthetankvolumeevery10–20minutes(slowerismoregentleonthefish).Icecanbeusedtochillthehaulingtankifneededonhotdays.

Once thewater in thehauling tank iswithin5°Cand1.0pHof thesystemwater, the fish can be quickly and gentlymoved into quarantine in the PurgeTank.UsethededicatedPurgeTankfishingnet.

QuarantineThefishwilltypicallyremainquarantinedinthePurgeTankfor1–2weeks.Thepurpose of the quarantine is to avoid spreading pathogens or disease to othercohorts.TheUVsterilizerswillgreatlyassistinpreventingthis,butallduecareshouldbetaken.Theintroductionofanewcohortfromanexternalsourceisthemosthigh-riskmomentforpathogenstoenterthesystem.

IMPORTANT

ThePurgeTankmustbeisolateduntiltheendofquarantine(notconnectedtothemainsystem).Supplementaloxygenmustbeaddedbyeitherthebackupoxygensystemorwiththeuseofasubmersiblecirculationpumptoagitateandaeratethewater.

As the Purge Tank is not connected to the main system, including thebiofilter,theammonialevelwillslowlyincrease.Testammoniaatleastonceperday.When it reaches1ppm,removehalf thewaterandreplace itwithsystemwater.Dothisasoftenasneeded.

IMPORTANT

Waterfromanexternalsource,suchasthehatchery,andwaterusedduringquarantinemustneverbeaddedbacktothemainsystem,theWasteTanksoranaturalbodyofwater(pond,stream,etc.).Itshouldalsonotbeusedtowatersoilcrops.Itcanbeusedtowatertreesormustbediscardedinafieldorsewer.

Observefishregularlyforsignsofdisease.Regardlessofwhetheranythingisseentobeproblematic,immediatelybeforemovingthefishtoTank1,givethema1%SaltBathTreatmentfor2–3hours.

LabelforBio-Oregonfeed.

FishFeedFishfeedisacontentiousissue,particularlyforcarnivorousspecies.Carnivorousfish typically eat other fish. The notion of feedingwild fish to farmed fish iscondemnedby some.Weacknowledge these issuesbutwill not be addressingthem in this book. We strive to use only the most environmentally friendly,ethicalfeedavailableandhopeyouwilldothesame.

Trout are carnivorous and require a high percentage of protein as well asessentialoils and fattyacids.Thequalityof feedvariesgreatly,particularly inconcentrations of oils and lipids. We use and recommend Bio-Oregon feed,

1.2.

3.

4.5.

madebySkretting,whichconsistsofby-productfrommarinesources.Likeallfish feeds, the content changes regularly based on the supply available to thecompany. This feed is “Best Aquaculture Practices Certified” by the GlobalAquacultureAlliance.

The protein alternative to marine-sourced feed is land-sourced, typicallyfromanimalsourcessuchaschickenorvegetablesourcessuchassoyorcorn.Withoutneedingtoconsiderthehugeenvironmentalandethicalproblemswithfactory-farmedanimalsandmonocrops(whichishowvirtuallyallsoyandcornisgrown), land-basedfeedsaregenerallylessdesirablebecausewhiletheycanmeetcrudeproteinneeds,thequalityofthefeedisgenerallyinferiorandlackstheneededoilsandlipids.

FeedingYourFishTheamountofdailyfeedisbasedonthebiomass(totalweightoffish)ineachtank, and thus increases as the fish grow. Keep track of the biomass byconducting regular sampling of the tanks and recording results on the CohortLogs.

SamplingSamplingistypicallydoneeverythreeweeksbyweighingafewsamplesofonecohortandusingthatdatatoestimatetheaverageweightperfish.Samplingdatais recorded in the Fish Sample Log, and the average weight per fish is thenrecordedontheCohortLogfortheappropriatecohort.TheCohortLogsareusedtotrackthegrowthrateandbiomassofeachcohortandtodeterminethedailyfeedrequirement.

Placeatoteofwaterwithalidonyourlargescaleandtaretheweight.Scoopapartialnet-fulloffishfromthetankusingthededicatedtanknetandplacetheminthetotewiththelidontopreventwatersplashingout.WaitafewsecondsforthescaletosettleandrecordtheweightofthesampleonFishSampleLog.CountthefishasyoureturnthemtothetankandrecordonFishSampleLog.Dividetheweightofthesamplebythenumberoffishinthesampletofind

6.7.

8.

theaverageweightperfish.RecordonFishSampleLog.Repeatsteps1–5threemoretimes,recordingthedatafromeachsample.Add together the average weight per fish from each of the samples anddivide this by 4 to find themean averageweight per fish.Record onFishSampleLog.RecordthemeanaverageweightperfishonCohortLog,noting“sample”in“Event”column.

Yourfeedmanufacturerwillhaveachartoftherecommendeddailyfeedratethatshowstheamountoffeedtogiveasapercentageofbodyweightforagivenwatertemperatureandsizeoffish.Ingeneral,fortroutin15°Cwater,youngerfish are fed approximately 2% of their body weight per day until they reachapproximately100g,afterwhichfeedisreducedto1.5%ofbodyweightperday,andthenfurtherreducedto1%beyond500g.Smallerpellets(3–4mm)arefedtotheyoungestfish,andastheygrow,thepelletsizeisincreased(upto9mmforthelargestfishwegrow).

FeedingTechniqueItisbetterforthebiofilteriffeedisdividedthroughoutthedayratherthangivenall at once, as that will create a spike in ammonia. The primary aim of theaquaponic farmer is system stability, so doing this is undesirable.While it isacceptableifnecessarytoinputallfeedatonce,strivetodividefeedovertwoorthreefeedingsthroughouttheday.

To feed by hand, simply scatter the feed onto the water surface. It willnaturallystartsinkingslowlyandshouldcauseafeedingfrenzywherefishjumpandcompeteforfood.Afrenzyisnormalandanindicationofgoodfishhealth.Ifthefishdonotfrenzy,thisisoftenthefirstcluethatsomethingiswrong.

Afeedingfrenzyisasignofhealthyfish.

If you choose to use auto-feeders, youwill require one for each tank.Theadvantagetoauto-feedersisthattheywilldividethefeedthroughouttheday,farbetter than ispossiblebyhand.Dependingon the sizeof the feeder, theywillallowyounottobeonsiteforaperiodoftime.Thedisadvantageisthatyouwillbelessintimatewiththebehaviorofthefish.Theactofhandfeedingdailyandwitnessing their statewhen fed is extremely useful in gauging fish health and

vitality.Anauto-feedertypicallycosts$300–1,000.Werecommendfeedingbyhandwithfeeddividedover2or3timesperday.

If you use an auto-feeder, select high-quality belt feeders and avoid demandfeederswhichletthefishdispensethefeedondemand.

FishTankRotationYouhavetwooptionsforraisingfish:raisetheminonetankfortheirlife(afterquarantine) or rotate them from tank to tank as cohorts are harvested. Theadvantagetousingasingletankisthattherotationprocess(nettingthefishfromonetanktoanother)isstressfultofish.Theadvantagetorotationisthatyoucanmorecloselymonitorthehealthandnumberoffishandyoucaneasilyremoveruntsfromthecohort.

Thisisapersonalchoice,asbothoptionsareacceptable.Werotateourfish,aswefeeltheopportunitytoobserveandcountthemoutweighstheirbriefstress.RotationalsoallowsustoeasilyperformaprophylacticSaltBathTreatmentandgivesustheopportunitytofullycleanandsterilizeeachtankonaregularbasis.

When transferring between tanks, carefully count the fish as you depositthemintotheirnewtankandrecordontheCohortLog.Usetheopportunitytosample the cohort and update the total biomass on theCohortLog. Itmay benecessary topartiallydrain the tank (store thewater in thecistern) inorder tomoreeasilycatchthelastfew.

TankCleaningandSterilizingAs fish tanks are open to light, algae will grow prolifically on the sides andbottom even if the tanks are covered with a shade cloth or other fabric. Ifallowed tobuildup, algaecanbecomedetrimental to the system.Thick layerswillconsumeoxygenastheygrowanddieandcanharborpotentiallypathogenicfungalsporesandbacteria.Itisimportanttoremovealgaeregularly.

Everyweek,usethededicatedbrushesforTanks1–3toscrubthewallsandfloorofonetank,rotatingweeklysoeachisscrubbedeverythreeweeks.Ifthealgaegrowbackquickly,youmayneedtocleanmorefrequently.

Scrubbingcanbedonewith fish in the tank—there isnoneed to remove

them or drain the tank. If there are large amounts of algae, the cleaningmayneedtobedoneinstagestopreventthewaterfromgettingtoomurky.Besuretoscrubthedrainscreenandthedrainsump,ifthetankhasone.

Sterilize a tank whenever it is empty of fish, such as when it is fullyharvestedor thefisharebeingrotatedbetween tanks.Empty the tankofwater(movetothecistern)andscruballalgaefromthewalls,flooranddrain.RinsethetankintothewastecollectionsystembypoppingtheSPA.

In a clean bucket, mix 15–20 mL of 30% hydrogen peroxide per liter ofwatertoscrubthetank.Useonlythededicatedtankbrush.Letstandforanhourbefore rinsingwell.At the same time, sterilize the dedicated tank net and thededicated scrubbrushby standing them in thebucketofH2O2 solution.Rinsewellbeforestandingthemtodry.ThetankcovercanbesterilizedbysubmergingitinabinofthesameH2O2concentrationforanhour.Rinsebeforedrying.

FishHealthTofullydiscussfishhealthincludingdiseases,symptomsandpathogenswouldrequire a voluminous scientific book.Wewill only scratch the surface in thisbriefdiscussion.

Fish health management consists of practices such as daily observation,recordkeeping,managementplansandbiosecurityprotocolsforthepreventionand treatment of diseases. Observations and record keeping will help you toidentifyandtreatpotentialproblemsearlyon,beforetheybecomecatastrophic.Havingatreatmentplanisparticularlyimportantforaquaponicsystems,asthereare few treatment options available that can be used without harming plantsand/or the biofilter. Below are two treatment protocols that we have foundparticularlyusefulforthepathogenswemostcommonlyencounter.

Biosecurityprotocolsareusedtopreventtheintroductionofpathogensintothe greenhouse as well as prevent the spread of pathogens between cohorts.Biosecurityprotocolsarean integralpartof the systemandshouldbeplannedduring the design phase. If you visit a hatchery, it will likely employconsiderablebiosecurity,andthisisagoodmeasureofthequalityofthefacility.

At a minimum, we recommend employing the following common sensebiosecurityprotocols:

•••••••

••

Nooutsidewaterentersthesystem(onlyyoursourcewater).Monitorfishcloselyandregularly.Nooutsidefishenterthesystem(e.g.,fromapond).Fisharealwaysquarantinedandsaltbathedpriortoenteringsystem.Feedisproperlystoredtoensurenomold.Visitorsdonotputanythingoranypartoftheirbodyinsystemwater.Farmersmustwashhandswithbiodegradableunscentedsoapbeforeputtinghandsinsystemwater.Usededicatedfishingnetsandcleaningbrushesforeachtank.Installfootbathsatallentrances(optional).

Themostimportantmethodsofgaugingfishhealthareexperienceandbeingintimatewiththenormalbehaviorofyourfish.Giventime,youwillknowhowfish look and act when healthy. By observing them closely, you will noticeanything out of the ordinary. This is a primary reason why we prefer andrecommendfeedingbyhand.

Observe the tanksdaily forsignsofdeadorweakfish.Deadfishwill firstsinktothebottomandifnotpromptlyremovedwillbegintofloatastheystarttodecompose internally. Remove them immediately, then sterilize the net usedwith hydrogen peroxide or formalin. Weak fish will likely first be noticedfloating near the surface and/or showing signs of lethargy and/or swimmingirregularly. Remove weak fish immediately, as they are more likely to hostdiseaseorpathogenswhichcaninfecttheentirecohortorsystem.Whileitmayseemcrueltodestroyalivingfishforbeingweak,youmustconsiderwhatitbestforthecohort.Ifyoueverloseawholecohort,youwillunderstandtheconceptofthegreatergood.Takemortalitiesoffsiteforcomposting.

It isnormal to losea fewfishover time inyour farm.Youarecreatinganecosystem where there is always variability of the conditions. In general, weconsiderlossesofupto5%ofacohortovera12-monthperiodtobewithintherangeofnormal.Someofthesewillbeweakorstuntedfishthatareintentionallyculled, other losses can occur from predation or jumping out of the tank. Ifseveralfishdieorbecomelethargicatonetime, it isaclearsignofaproblemthatrequiresimmediatecorrectiveaction.

Pathogens are microorganisms that cause disease. They are highly

opportunistic andwill alwaysbearoundyour systembut for themostpart arekept in check by the UV sterilizers, good biosecurity practices and raisinghealthyfish.Thenumberonecauseofapathogenordiseasetakingholdisfishstress.Asinhumans,therearemanyprecursorstostress.Themostcommonareinstability insystempHor temperature, lowoxygen,highammoniaornitrites,physicaldamageduetoovercrowding,greatlymismatchedfishsizesinthesametankandmovingfishfromonetanktoanother.Yourjobistokeepthesystemstableandminimizestresstothefishhoweverpossible.

Oneofourearlycohortlosses.Thisiswhatyouaretryingtoavoidatallcosts.

The most common pathogen we encounter is Flavobacterium, which cancause several diseases, most commonly Bacterial Cold Water Disease.Symptomsincludelethargyandirregularswimming,followedbyfinrotandskinlesionsandeventuallydeath.Fin rot is identifiedbywhitenessaround the finsandfrayed,erodedorcompletelymissingfins.Skinlesionsbeginaspatchesof

discolorationandprogresstoopensoresifuntreated.Seecolorphoto.If we witness a low level mortality problem (1–5 fish dying per day) or

noticeanothersustainedsymptomforlongerthanafewdaysthatisnotdirectlyattributable to poor water quality (high ammonia or nitrites), we immediatelyperform a Hydrogen Peroxide Treatment. If after two treatments the problempersists,weperformaSaltBathTreatment.

IMPORTANT

Atthefirstsignofanyproblem,whetheritispotentialdiseaseorwaterquality(highammonia,lowoxygen,etc.),immediatelyceasefeedingallfishinthesystemuntiltheproblemisidentifiedandresolved.

HydrogenPeroxideTreatmentHydrogenperoxide(H2O2)iscommonlyusedinfreshwateraquacultureforthetreatment of external fungal, bacterial and parasitic infections. H2O2 naturallydegrades to water and oxygen by a variety of chemical and biologicalmechanisms, including enzymatic decomposition by algae and heterotrophicbacteria.Bacteriaaccountforthemajorityofdegradation.

Duetoitsrapiddegradation,hydrogenperoxidecanbeaddeddirectlytotheculture tank without first moving fish to a quarantine tank or discarding thetreatmentwater.Althoughhydrogenperoxidewillnotharm thebiofilterat therecommended concentration, it can harm the fish at slightly higher than therecommendedconcentrationbyscarringthegilltissuesandcausingsuffocation.Caremustbetakentocalculatethedosagecorrectly.

H2O2Treatmentslastforamaximumof60minutesataconcentrationof50–75 ppm. Consecutive treatments may be carried out every second day to amaximumofthreetreatments.

TocalculatetheamountofH2O2requiredforaconcentrationof50ppm(50mg/L):

1.

2.

3.

4.

1.

Calculatethevolumeofwaterinthetankbymeasuringthetankradiusandtheheightofthewater(usingtheformulaforacylinder):

(π)×(Radius2)×(Height)=Volume

Forexample,inan8′tankwith3′ofwater:

(3.14)×(122cm×122cm)×(90cm)=4,206,218cm3=4,206L

Calculatethecorrectionfactorforthestrengthofhydrogenperoxideyouareusing.

Acorrectionfactorisusedwhenevertheadditivecomponentisnot100%activeingredient.Inthiscase,thehydrogenperoxideproductcontains30%H2O2(theactiveingredient)and70%water.Forexample,using30%“technicalgrade”H2O2:

Correctionfactor=(100)/(30)=3.3

CalculatetheamountofH2O2tobeaddedtothetank:

(volumeoftank)×(dosageofH2O2)×(correctionfactor)=amountH2O2

Forexample:

(4,206L)×(50mg/L)×(3.3)=693,990mgH2O2

AsH2O2 isa liquid, it isdesirable toconvertmilligrams(mg) tomilliliters(mL):

(693,990mg)/(1,000mgpergram)=694grams(rounded).

(694grams)×(1grampermilliliter)=694mL

Fromthisexample,wecanseethatforatankwith4,206Lofwater,694mLof30%strengthhydrogenperoxideyieldsaconcentrationof50ppm.

ToperformtheH2O2Treatment:

Isolate a tank by shutting off the water inlet and turning on the backupoxygentothattank.PlaceasubmersiblepumpinthetanktokeepthewatercirculatingandusetheDOmetertomonitoroxygenlevels.

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MeasuretherequiredH2O2,followingtheexampleabove,anddiluteitina5-gallonbucketofwater.Slowlypour thebucket into the tankoveraperiodofat least fiveminutes,ensuringitiswellmixedsothatnofishareexposedtohighconcentrationsofH2O2.MonitortheDOlevelsandobservethefishforsignsofstress,suchasirregular swimming (on their side) or gasping at the surface. If stress isobserved, double-check that you calculated the dose correctly and turn thewaterinletontodilutetheH2O2.After 45–60 minutes, turn the tank inlet back on. Remove the circulationpumpandturnthebackupoxygenoff.

SaltBathTreatmentASaltBathTreatmentiseffectiveintreatingmanycommonbacterialpathogens.The treatment causes a pathogen to enter a state of osmotic imbalancewhichkillsit.

IMPORTANT

Saltistoxictotheplantsandbiofilter.Itiscriticalthatthetreatmentwaterisneverallowedtoenterthesystemwater.TreatmentsarealwaysdoneinthePurgeTank,andthetreatmentwaterisdiscardedafterwards.

Fishcanbetreatedfor2–3hoursormoreatasaltconcentrationof1%(10gper liter) so long as they show no signs of irregular swimming or surfacegasping.Aconcentrationofupto3%(30gperliter)canbeusedforshortbathsof10–30minutessolongasfishshownosignsofstress.

Ceasefeedingthecohort24hourspriortotreatment.Isolate the tank from the system: shut off the water inlet and turn on thebackup oxygen to that tank. Use the oxygen meter to monitor DO levelsduringthetransferprocess.

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Use a submersible pump to transfer thewater. Fill the Purge Tank¾ fullwithwaterfromthefishtankthatistobetreated.Turn on the oxygen to the Purge Tank andmonitor DO levels during thetreatment.CalculatethevolumeofwaterinthePurgeTankusingtheformuladescribedintheH2O2treatment:(π)×(R2)×(H).Add 10g of salt per liter of water in the tank, to achieve a 1% saltconcentration. Dilute salt in a 5-gallon bucket of water before adding toPurgeTankovera5-minuteperiod.Use thesubmersiblepump tocirculatethewaterinthePurgeTank.Transferfishintothesaltbathasquicklyandgentlyaspossible.Inordertocatchallthefish,youwillneedtodrainmostofthewaterfromthefishtankbysiphoningorpumpingitdowntothesumporcistern.

IMPORTANT

Useonlypuresodiumchloride(NaCl).Neverusede-icingsaltoranythingwithanti-cakingagentsoranyotheradditives.AlwayschecktheMSDSoftheproducttoconfirmthatitispure.Manybrandsofpoolsaltcontainadditives.WeuseWindsorpoolsalt,widelyavailablefrompoolsupplystores.

Leave fish in the saltbath for2–3hours,observing frequently for signsofstress,suchasgaspingatthesurfaceorswimmingontheirsides.Ifanyofthesesignsarenoticed,double-checkthatyoucalculatedtheamountofsaltcorrectlyanddilutewithmorewateruntilthefishcanbetransferredbacktotheirtank.

Duringthetreatment,usetheopportunitytocleanandsterilizethefishtank.Scrubanyalgaeandbiofilmoff thewallsandfloorandflush itdownthe tankdrain.Sterilizethetankwithastrongsolutionofhydrogenperoxide:15–20mlof30%H2O2perliterofwaterinacleanbucket.ScrubtheentiretankwiththeH2O2solutionandletitsitforanhourbeforerinsingdownthetankdrain.

Torefillthetank,turnonthewaterinlettoreconnectittothesystem.Whenfilling the tank, monitor the water level in the sump. Top up the sump with

cisternwaterasneeded.DonotfillthetankdirectlywithcisternwaterthathasnotbeenUVtreated.Thetankmaybetoppedupwithsourcewaterifyouhavenocistern.

IMPORTANT

Discardthesaltwater.DonotdrainitintothesystemorWasteTanks.

OncethetankisbackonlineandfishhavebeentreatedinthePurgeTankfor2–3hours, remove the circulationpump from thePurgeTank and transfer thefishbackto their tank.Turnoff thebackupoxygentoboth tanksandreset theoxygensystemsothatitisreadyforthenextemergencyevent.

LabAnalysisTo be certain of the disease or pathogen infecting your fish, youwill need tosendone to a lab for analysis.The labwillwant the fish as fresh aspossible,ideallylive,whichwillrequireshippingthefishonice.Earlyonwesentfishtoalabonseveraloccasions.Wehavenothadtodosoforafewyears,aswehavefound that close fishmonitoring, H2O2 Treatments, Salt Bath Treatments andbasicbiosecurityprotocolsresolveallissues.

PurgingBeforeHarvestPurgingisrequiredforfishinallrecirculatingaquaculturesystems,especiallyinaquaponics. Recirculating systems provide an excellent environment for thegrowth of problematic varieties of bacteria, notably actinomycetes andcyanobacteria, and some species of algaewhich produce twometabolicwastecompounds:geosminand2-MIB.Theseorganicmoleculesarereadilyabsorbedby fish and can impart a strongmuddyor earthy flavor to the flesh.They are

detectablebyhumanpalatesatconcentrationsintheparts-per-billionrange.

Purgetankwithsubmersiblepumpforaerationandcirculation.

Purging, sometimes known as depuration, is a process of eliminating thebacteria and algae from the water and allowing the geosmin and 2-MIB todiffuse out of the flesh. This is done by holding the fish without feed in thePurgeTankfor10–15daysandexchangingatleast25%ofthepurgewaterwithcleansourcewatereveryday(50%forthefirsttwodays).

As thePurgeTank is isolated from the restof thesystem,oxygenmustbesupplementedviathebackupoxygensystemorbyusingasubmersiblepumpinthetanktoliftwaterandsprayitbackintothetank.Withholdingfeed24hoursbefore transferring fish to the Purge Tank will dramatically decrease theiroxygenconsumption.

Ammoniabuildupisnotanissuebecauseofthelackoffeedanddailywaterchanges.TemperatureshouldnotbeanissueaslongasthePurgeTankdoesnotgoabove20°C.Iftemperatureisanissue,useacirculationpumpconnectedtoa

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water chiller. Temperatures below 10°C are preferred as they will inhibit thegrowthoftheundesirablebacteriaanddecreasefishmetabolism,whichinturnwilldecreaseoxygenconsumptionandammoniaproduction.

A small UV sterilizer connected to the circulation pump is a beneficialadditiontothisprocess,asitwilldestroyanyundesirablealgaeorbacteriathatmay be present in the purge water. The UV sterilizer will not destroy thegeosmin or 2-MIB compounds produced by these organisms, so daily waterexchangesmuststillbeperformed.

Donotharvest a cohort all at once, as thiswill remove toomuchbiomassfrom the system. The number of fish you harvest will be dictated by totalbiomassofthesystemandyourmarketdemand.

For average 1 kg fish, we recommend filling the Purge Tank half full topurge20 fish.Fill thePurgeTank to three-quarters full forup to40 fish.Youmay be able to purge more biomass than this in a full Purge Tank, but werecommendharvestingnomorethan20–30fishatatime.

PURGEPROCEDURE

Sterilize the Purge Tank with hydrogen peroxide: add 15–20 mL of 30%H2O2perliterofsourcewaterinacleanbucket.Scrubtheentiretank.Letsitforanhourthenrinsedownthetankdrain.FillthePurgeTankwithanappropriateamountofwaterforthebiomasstobepurged.Use50%systemwaterand50%sourcewater.The temperaturemust bewithin 5°C and the pHwithin 1.0 of thewater the fish are beingmoved from. Usemore or less source water if needed to bring the PurgeTankwithintheseparameters.Place a submersible circulation pump in the tank or turn on the backupoxygentothePurgeTank.MonitoroxygenlevelwiththeDOmeter.MovefishtothePurgeTank.Trytomovethelargestfish,althoughtheyaretypicallyfasterandhardertocatch.

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IMPORTANT

Donotfeedfishbeingpurgedatanypointinthepurgeprocess.Additionally,ceasefeedingthewholecohortfor24hourspriortomovingfishtothePurgeTank.Resumefeedingthecohortoncefishtobepurgedaremoved.

For the first twodays, exchange thepurgewaterbypumpingor siphoning50%ofitintothesumpandrefillingwithsourcewater.Aftertwodays,only25%ofthepurgewaterneedstobeexchangeddailyforthedurationoftheprocess.Neverusecisternwaterorsystemwatertopurge,as it contains the undesirable bacteria and organic compounds. Use onlysourcewaterfordailyreplacement.Waterusedinthepurgeprocesscanbeaddedbackintothesystemorstoredinthecistern.After aminimumof tendays, test thequalityof your fishby cooking andtastingafilletwithoutseasoningorbutter.Ifyoutasteevenahintofmuddyorearthyflavors,continuepurging.Alwaystastetestyourfishbeforesellingthem, as conditions are inherently variable and the time it takes for theorganiccompoundstodiffusefromthefleshcanvarywithconditions.

HarvestingFishLet’sbehonestattheoutset:whenwetalkaboutharvestingfish,wearetalkingabout killing. There aremanymethods and ethics regarding the harvesting offish.Wehavetriedmanymethods, includingCO2gassingandsedation.Inourexperience,andaccordingtostudiesdonebytheHumaneSocietyoftheUnitedStates,thequickestandmostassuredmethodofkillingafish,andthusthemostethical,isalsothesimplestandoldest:hittingitontheheadwithabluntobject.Weuseahardwoodfishbatforthispurpose.Ithastherightweightandfitsthehandnicely.Youwilllikelyneedtoexperimenttofindtheobjectthatworksbestforyou.

Themethodisverysimple:removeafishfromthePurgeTankandwhileit

is stillwrapped in thenet andeasy tohandle, strike ithardon theheada fewtimes.Agoodhitwill instantlykill it.Witha littlepractice, thismethodis thequickest,surestandmosthumane.Removethefishfromthenetandcutitsgillstobleedit.

Optionally,justbeforeharvest,youcanputbagsoficeintothePurgeTanktoquickly lower the temperature, putting the fish into anearly catatonic state.Doingthiswillalsoprechillthefleshanddelayrigormortis,whichmayormaynotbedesirabledependingonyourmarket.

Freshlykilledfishwithfishbatandknife.

Confirmwith your local health authoritywhat level of processing you areallowed to do onsite. Depending on your intended market, you may requirecertificationforprocessing.Insomecases,youmaybeabletoremovethegutsand gills before selling aswhole fish, direct to consumer,without requiring a

slaughterorprocessingpermit.Ifyouwant to furtherprocess fishonsite,youwill likelyrequireaspecific

food-processing license that may require the addition of a separate healthauthority-approvedbuildingorkitchen.Alwayscheckyourlocalregulations.

Harvested fish must be immediately put on ice, moved to the cooler orfrozen.

P

PlantProduction

LANTS ARE THE PRIMARY SOURCE OF INCOME on an aquaponic farm. Ourmultistageproductionsystemisdesignedtomaximizespaceatallstagesof

growth,thusmaximizingyieldsandprofit.TheDWCtroughsarethemostvaluablerealestateinyourfarm.Thepriority

istominimizethetimerequiredbyeachplanttocometomaturityandtohaveaconstantsupplyofnewseedlingsreadytobetransplantedintothetroughs.Thebiggest challenge, other than control of the environment, is applying a humantimeline(aweeklyplantingschedule)toanecosystemthatgrowsatitsownpaceandchangeswiththeweather.

PlantSelectionManyplantsthriveinacold-waterDWCsystem,andmanydonot.Thekeyistofindplantsthatthriveinyoursystemthatyoucaneasilymarketatagoodprice.Theparametersofthesystemarenotasadaptableasyourchoiceofplants.Ifaplantdoesnotthriveoryoucannoteasilysellit,growadifferentplant.

In general, you can separate plants into two categories: thosewith slowergrowth that will be grown in stages and those with faster growth (6 weeksmaximumfromseedtoharvest)thatwillbedirectlyseededintothetroughs.

ThePlantsWeProduceatRCAWe have tried the following plants/families and found that they thrive in oursystem: lettuce, mustards, watercress, kale, mint, the choi varieties, cilantro,

Swisschard,leeks,beans/peasandcelery.Wehavetriedthefollowingplantsandfoundtheydopoorlyinoursystem:

spinach,strawberries,tomatoesandbasil.Spinachinparticularwassurprisingtousasitisacool/wetseasoncrop,butitseemsthatitdoesnotlikewetfeet(rootsconstantlywet).

Therearemanycropswehaven’ttriedbutassumetobeineligibleforotherreasons: root crops such as carrots and potatoes may rot underwater, winterbrassicaslikecabbageandbroccolisimplytaketoomuchspaceand/ortoolongtogrow,andothercropslikecornandsquasharephysicallyincompatibleduetotheirsizeand/orspread.

Even though they growwell, we do not producemint, the choi family orSwisschard,astheyarechallengingtomarketorthemarketpriceistoolow.Wedonotproducebrassicasorbeans/peas,as they take toomuchspaceand time,nor cilantro which takes a long time to sprout and is prone to bolting in ourclimate.

Some plants, such as watercress, grow exceptionally well. We producedlargequantitiesonlytofindthatwhileitisindemandandsellsatapremium,thelocaldemandismuchlessthanourproductioncapacity,andweendedupwithconsiderableunsold stock thatbecamecompost.Determining the rightbalancebetweenaplant’scapacitytothriveinyoursystemandthelocaldemandforitwilltakeexperimentation.

Of the plants that thrive, we have narrowed downwhat we produce on aregularbasistothreevarietiesoflettuce,threevarietiesofmustards,watercressandbabykale.Wealsogrowsmallamountsof leeksandceleryonaseasonalbasis.Forus,theseplantshavethebestbalanceofspeedofproduction,easeofmarketingandthehighestprofitsfromsale.

We grow green leaf, romaine and butterhead lettuce. We recommendexperimenting to find the types that thrive in your system, then reducingyourregularproductionto3–6varieties.WegrowTropicanagreenleafwhichislargeand robust,Coastal Star romainewhich has a classic blanched heart structure,andAlkindusandRoxybutterheadswhichareabrilliant redcolorwith tenderblanchedhearts.Wehavetrieddozensofothervarietiesof lettuce,withvariedresults,andcontinuetotestnewvarietiesregularly.

Mustards growverywell in our system.WegrowGiantRed,Mizuna and

Red Kyona Mizuna. All three thrive and produce vibrant, thick leaves withvaryinglevelsofspice(GiantRedisthehottest).

Watercressisperhapsthemostvigorousplantwe’veevergrown.Wegrowtruewatercress(Nasturtiumofficinale).Incontrasttocurlycressorpepper-cress,truewatercressisarich,darkgreenwithrobuststalksandleaves.Itisfirmandcrunchywith a spicy fresh flavor, growsquickly and is very resistant to pestsanddiseases.

WegrowavarietyofkalecalledAbundance,typicallyasababyleaf,thoughitcanbegrowntofullsize.Weharvestoursyoungtoaddtooursaladmixorsellinbulk.

Bothwatercress andkale are fast-growingplants that canbedirectly sowninto the troughs (no separate sprouting or seedling stage) to save on labor.Becauseofthetimeittakestogrowthemtomaturity,lettuceandmustardsaresprouted in the Germination Chamber and grow in the seedling area prior toplantinginthetroughs.

On average, lettuce accounts for approximately 75% of the plants weproduce.Weproduce a little less romaine thangreen leaf andbutterhead.Theremaining25%issplitbetweenwatercress,mustardsandbabykale.Theexactplanting of each crop depends on a variety of factors, notably what growsparticularlywellduringthatseason,whichseedlingsarethestrongestandwhatisinmostdemandatmarket.

SeedsThere are numerous seed producers to choose from. Sampling andexperimentationwillberequiredtodeterminethebestproducerforyourfarm.Ingeneral,werecommendproducersoforganic,non-GMOseeds thatare locatednearyouand/orwithinasimilarplanthardinesszone.WebuyallofourseedsfromWestCoastSeeds,aBCcompany.Werecommendthem.

The quality of seeds will vary from year to year, even from the sameproducer.Raisingplants (and seeds) is always impactedbynature.Good seedproducerswillbeabletosomewhatbuffertheeffectsofanoffseason,butseedqualityvarianceshouldbeexpected,particularlyfromproducersoforganic,non-GMOseed.

For lettuce, look for varieties that grow vertically more than horizontally.This will allow more plants per raft without crowding, and low-growing(horizontal) lettuce tend to suffer more from bugs and rot around the stems.Romaineisanexcellentexampleofalettucethatgrowsvertically.Butterheadisanexampleofalower,wider-spreadingplant.

IMPORTANT

Ifavailable,westronglyrecommendpelletedseeds.Pelletedseedsareencasedinasmallballofclaywhichquicklydissolveswhenmoistened.Theyaresubstantiallyeasiertohandle,makingitquickertoplantoneseedpercell,whicheliminatesthinninglater.

Pelleted(left)andnon-pelleted(right)lettuceseedsshownwithaquarterforscale.

Seedsmustbestored inacool,dry,darkplace that isprotected frombugsandvermin.Improperstoragecanspoilorgreatlyreducetheirviability.

TheGrowthCycle

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The growth cycle of a plant will vary depending on the time of the year,primarilyduetofluctuationsinphotoperiodandairtemperature.Thetwotypesofproductionaremultistage(transplanted)anddirectseeding.

Atypicalmultistagegrowthcycleis:

1weeksproutingintheGerminationChamber.3–4weeksgrowingfirstleavesontheSeedlingTable.3–6weeksgrowingtomaturityinthetroughs.Note that larger plants are thinned or spaced half way through the troughstage.Lettuce,mustards,cilantro,Swisschard,leeks,beans,peasandceleryareall

growninamultistagecycleastheyalltakefourweeksormoretogrowintoa3–4″seedlingfromseed.Althoughamultistagecyclemakesmoreefficientuseofspace,italsoinvolvesmorelaborduetotheadditionalstepsoftransplantingandspacing/thinning.

DirectSeedingDirectseeding issowingseedsdirectly intonetpotsand inserting into troughswheretheywillgerminateandgrowuntilharvest.Watercressandbabykalearegrown in thismannerbecause theycan reachaharvestable size in4–6weeks.Thegoalisadensecanopythatcanbeharvestedenmasse.Spacing/thinningisnotrequired.

Foreachraft:

Place a thin layer of transplanting media (coarse coco chips or looserockwool)atthebottomofeachpot.Thepurposeofthetransplantingmediais to create a physical barrier that prevents the growingmedia around theseedling from washing out. A few flakes of coco chips or ¼″ of looserockwoolwillsuffice.Add a layer of germination media (coco coir or Pro-Mix) on top of thetransplantingmedia.Thereisnoneedtopresoakthemediaasitwillwickupenoughwaterfromthetroughtomoistentheseeds.At theworkbench, insert thepots intoa raft and sprinkle seedsdirectlyontopofthemedia.Babykaleisseededat10–15seedsperpot;watercressat15–20seedsperpot.

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Place raft in trough. If the air is very dry, itmay be necessary to looselycover the raft with a sheet of clear plastic until the seeds germinate. Themedia will wick up the water from the trough, moistening the seed andstartinggermination.Bothwatercressandkalegerminatein2–3daysunderidealconditions.

Ifyouusedaplasticcovering,removeitoncetheseedshavesprouted.Oncethecrophasbegun to formacanopy, rafts shouldnotbemoveduntilharvest.Thereisnoneedtothinorspacebabykaleorwatercress.

MultistageProductionPlantingSeedsTheGerminationChamberholds18seedtrays,eachwith98cells.Thismeansyou will be seeding 1,762 new cells every week. Like all aquaponic tasks,efficiencyiskey,sothinkofitlikeafactoryline.

To speed up the process of pressing holes into the media for the seeds(dibbling),useadibblerplatethatcandibbleawholetrayatatime.SeeDibblerPlate,Chapter5.

Filltheworkbenchwithtrays,bumpertobumper.Spread seedlingmedia (coco coir or Pro-Mix) over all trays, gently fillingthecells.Use a submersible pump, hose and diffusingwand towater the trayswithtroughwater(usethesamesetuptowaterseedlings).The water will cause the media in the cells to compress. Gently addadditional media to fill all cells. No additional water is required, as theadditionalmediawillwickwaterupfromthewetmedia.Useadibblerplatetopressshallowholesintoeachcell.Placeonelettuceseedineachcell,or1–3ifusingnon-pelletedseeds.Ifyouare growing plants that are intended to grow as a bunch but are slowergrowingthusnotdirectseeded(e.g.,cilantro),place5–10seedsineachcell.Formustards,place3–6seedspercell.

Wehavetriednumeroustoolsandgadgetstomaketheseedplantingprocess

moreefficient.Nothinghasprovenanyfasteroreasier thanseedingbyskilledhand.Pelletedseedswillgreatlyimproveefficiencyastheymakeitveryeasytoplace only one seed in each cell. If using non-pelleted lettuce seeds, youwillneedtopracticeplacingasmall“pinch”of1–3seedsineachcell,andthesewillneed to be thinned to one per cell after germination. Buy pelleted seeds ifpossible.

Unlesstheymustbegerminatedindarkness,donotcovertheseedswiththegrowing substrate, simply leave them on the surface.Do not addmorewater.Place a low-humidity domeover each tray to keep seeds fromdrying out andmovethemtotheGerminationChamber.

Newlyseededtrayswithdomelids.

IMPORTANT

Manyseedscanbegerminateddirectlyontopofthemedia(notcoveredbymedia)aslongasthetrayiscoveredwithahumiditylid,whileotherseedsmustbesownunderthemedia.Lettuce,forexample,willnotgerminatewithoutsomelightontheseed,whereascilantroandparsleywillonlygerminateincompletedarkness.Refertotheinstructionsprovidedbyyourseedmanufacturer.

GerminationSeedswillspendoneweek in theGerminationChamber.This isnota flexibletimeline, as it is necessary to have a constant supply of seedlings ready totransplant, in order to operate at full capacity. If you find that plants do notsufficiently sprout in one week with good environmental conditions, considerdifferentvarieties.

The Germination Chamber is kept at 17–18°C. With the recommendedheating and cooling system (seeChapter 4), it should be possible to keep thechamberconsistentlyinthisrangeineventhemostextremeweather.Eachofthetwochambertablesholdsninetrays,witheachtablelitbythree3′T5bulbs.Werecommend20hoursoflightperday.

During the week of germination, your only job is to ensure the correcttemperatureinthechamber,whichisautomaticallycontrolledbythethermostat.Donotopenthedomesanddonotaddanywater.

ItispossibleduringthemilderseasonstogerminateinthegreenhouseontheSeedlingTable,butwerecommendagainstthis.YourGerminationChamberisdesigned to do a specific job and once dialed in should germinate a highpercentageofseedsrapidly.Additionally,whenyouareoperatingatcapacity,allproductionareasshouldbefull(orveryclosetofull)atalltimessoyoushouldnothaveroomonyourSeedlingTable.

SeedlingsAfter one week, the trays are moved from the Germination Chamber to the

Seedling Table to make room for the next week’s planting. Place newlygerminated trays directly under the grow lights as younger plants (oncesprouted) require the most light. This may require a bit of strategicrearrangement. Leave the domes on the trays for 2–3 more days unless thesproutsaresotallthattheybegintotouchthedome.

For most of the year, seedlings are watered once a day, twice if it isparticularly dry. Water only in the morning or the evening — never in themiddleofthedayorinveryintensesunlight.Inthewinter,highhumiditymakesitharderforwatertoevaporatefromleafsurfaces,andstandingwaterleftontheleavesfromirrigationcansmotherthemandinvitedisease.Duringthesetimes,itis better to water the seedlings less (every other day, as long as they aren’tdrying out), and to water only in the late morning so that the leaves have achancetodryduringtheday.

Ifyousowedmorethanoneseedperpotforplantsthatwillgrowoneplantperpot(suchasnon-pelletedlettuceseeds),trayswillneedtobethinnedbeforethecellsgettoocrowded(typically2weeksaftergermination).Gentlypulloutthesmallerorweakerseedlings,leavingonehealthyseedlingineachcell.

OurSeedlingTable.

Seedlingsshouldgrowonaverageto2–3″tallin3–4weeksintheseedlingarea. The conditions of the seedling area will be the same as the rest of thegreenhouse.ThesupplementalHIDlightsareusedonthesamescheduleasthesupplemental trough lighting. The lighting schedule is based on the targetphotoperiod(~14–16hours)andtheamountofsupplementallightneededforthetimeofyear.SeeSupplementalLightinginChapter2.

TransplantingintotheTroughsThe primary factors for determining which seedlings to transplant are thematurity of the seedlings and your knowledge of what yourmarket demands.Onceyouhaveanestablishedmarket,plantmaturityistypicallythedeterminingfactor.

Thenumberofraftstotransplantwillvarythroughouttheyearprimarilydueto the length of time plants take to grow to full maturity in the troughs. Ourlettuceisreadyinaslittleasthreeweeksunderperfectconditionsandcantakeas long as sixweeks in thewinter. The quantity of seeds planted can also beadjusted once you are familiar with the seasonal effects on your productiontimelines.

Ifyouachievea95%successrateforgerminationandseedlinggrowth,eachseedlingtraywith98cellswillfillapproximatelythreerafts(96sites).Asyoushould not expect to achieve a 95% success rate until you have had somepractice,boththeGerminationChamberandSeedlingTableareoversized.

Youneedthefollowingitemsfortransplanting:washedrafts,cleannetpots,transplantingmediaandatransplanttool.Allitemsshouldbelocatednexttotheworkbenchforefficiency.

Ourhigh-techcustomtransplantingtool.

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Unlesstheseedlingsarelargeandroot-bound,youwillneedatransplanttooltoremovethemfromthecellsandplacetheminthepotswithoutdamage.Makeyourowncustomtoolbytakingakitchenforkandbendingthetinestocreateasmallspade.Withsomeexperimentation,youcancreateashapethatfeelsgoodinyourhandandfitsperfectlyintothecells.Youwillbedoingthisactionmanythousandsoftimes—extratimespentcreatingthebesttoolwillpayitselfbackmanytimesover.

Place32netpotsontheworkbench.Place a thin layer of transplanting media (course coco chips or looserockwool)atthebottomofeachpot.Gently removea seedlingwith the transplant toolandplace in thenetpot.Gentlyseatthepluginthecoarsemedia.Repeat to fill all pots.Asmuch as possible, plant each raftwith the samevariety.Placearaftontheworkbenchandfillwithtransplantednetpotsthenplacetheraftintoatrough.

Transplantmediainbottomofnetpot.

Repeatuntilthetroughsarefulloraccordingtoyourtransplantschedule.

Gentlyremoveremoveseedlingfromitscellwithtransplanttool.

Placeseedlingintonetpot.

Freshlytransplantedseedlings.

Placenetpotsintoraft.Placeloadedraftintotrough.

RaftPlacementandRotationTheplacementofraftsshouldbedoneinaconveyormethod.Waterenters thewest endof thenorth sideof each trough, flows to the eastern end then loopsback, flowing east to west down the south side of the trough. The highestconcentration of nutrients is found at the trough inlet, just after the fish tankswhichproduce theconstituentnutrientsand theCFBwhere theyareconvertedintominerals.Theyoungeraplant,themorelightandnutrientsitrequires(thinkhowmuchmoreateenagereatsthananelderlyhuman).

Aplant(andhuman)willalwaysgrowbiggerandhealthieriftheyaregivenamplesunlightandnutrientswhentheyareyoung,evenifthelightandnutrientcontentdiminisheswhentheyaremature.Accordingly, thenewlyplantedraftsareplaced in themostupstreamspaces in the troughs.As theplantsgrow, therafts are moved downstream. Each week the most mature rafts are harvestedfrom the outlet end of the troughs, and all the remaining rafts are shifted

downstream to make room for new seedlings at the inlet end. During thisprocess,anycropsthathavebeguntocrowdshouldbespacedorthinnedtogivethemmoreroom.

TransplantScheduleForanumberofpotentialreasons,itisunlikelyyouwillbeabletokeepanexacttransplanting schedule. Most commonly, this is due to the varying seasonalproductiontimes.Itisimportanttoalwaysthinkaheadtoyourmarket.

For example, if you know (or estimate) that your production time is fiveweeks, you should be harvesting and transplanting ¹⁄₅ of your rafts weekly(approximately 50 rafts). If for some reason you have⅓ of the trough spaceavailablefornewplants,perhapsduetodiseaseoraone-timelarge-volumesale,strive to fill all the rafts through a combination of transplanting seedlings anddouble-spacing semi-mature rafts (rather than thinning). Asmuch as possible,useallgrowingspaceatalltimes.Thinkaheadandmakeaplanforsellingtheexcessproduction,suchasasalepriceoncertainproductsatyourmarketboothorwholesalingtheexcess.

The goal in an aquaponic farm is a consistent, year-round supply at themaximum efficiency of the system with maximum efficiency of labor. Thismeanskeepingthetroughsfullyplantedatalltimes.Onceyouarefamiliarwithyoursystem,includingseasonalproductionchanges,andknowthedemandsofyourmarket,youwillbeabletocreateaworkabletransplantschedule,butitisimportanttoremainflexibleasfarmingrequiresadaptability.

IMPORTANT

Rememberthat“productiontime”inthisbookmeansthetimeaplantspendsinthetroughs.Germinationandseedlingstagesareneverincludedin“productiontime.”

ThinningandSpacingPlants

Ourraftsaredesignedtoholdupto32plantsat6″centers.Withmanyplants,notably lettuce, this is not sufficient spacing to produce tomaturity.Typicallyaround half-way through their time in the troughs, plants will start crowdingeach other, causing numerous problems. Notably, they will deform as theystretchtocompeteforlight,andhavingasolidcanopyofplantsallowsbugsanddiseasetoflourishinthemoistdarkareasunderneaththecanopyandaroundthestems.

Wegrowplantson6″ centers for roughly the firsthalfof theirproductiontimeas this is thebestuseofspace(ourprimaryhydroponicdesignprinciple).Sproutsfitintolessthan40squarefeetintheGerminationChamber;seedlingsfitinto125squarefeetontheSeedlingTable,thentheyarespacedat32perraftuntil they start crowding. Once the leaves begin to touch their neighbors, thecrop is spaced to 16 plants per raft by thinning or spacing to yield a plant ineveryotherhole,whichwill look likediagonal rowsofplants.At16 sitesperraft,spaceddiagonally,plantswillbeon8.5″(diagonal)centers—sufficientformostplants,includinglettuce,togrowtomaturity.

Thinningmeans removing plants altogether from the troughs. If the plantsareparticularlyweakordiseased, theyarecomposted. If theplantsare simplystuntedorotherwise lessvigorous, the acceptableparts canbeused in a saladmix.Whenthinningaraft,removehalftheplantsbychoosingthesmallestandweakest or any that are showing signs of pest or disease, and then gentlyrearrangetheremainingplantsintothedouble-spacedconfiguration.

Spacingmeansmovingeveryotherplanttoanemptyraft.Afterspacing,the32plantsfromoneraftwilloccupytworafts(16perraft).

IMPORTANT

Whetherthinningorspacing,usetheopportunitytoquicklyinspectforandremoveanymoldyleavesfromtheundersidesoftheplantsorthetopoftherafts.

Thedecisionofwhethertothinorspaceplantswillbebasedonthequalityof the plants and the needs of yourmarket. If, after harvesting, there are onlyenough empty rafts to hold thisweek’s transplants, thinning the crop ismoreappropriate. If there are extra empty rafts, perhaps due to a large harvest or apreviouslackof transplantableseedlings,spacingthecropismoreappropriate.Onmostoccasions,youwillbeboththinningandspacing.Thinningandspacingtakesplaceafterharvestcleanupandbeforetransplanting,thusallowingyoutogaugehowmuchfreespacethereisforthenewtransplants.

IMPORTANT

Afterthinningorspacing,placeacleanemptynetpotintotheopenholesofeveryrafttoshadethewaterfromexcessivesunlight,whichcanharmthebiofilmonthebottomofthetrough.

Butterheadlettuce:singlespacing(rightraft)anddoublespacing(leftraft).

MaturingPlantsAfteracrophasbeenthinnedand/orspaced,theplantswillsoonbegintotouchagain andwill eventually form a canopy. This is acceptable as the process ofspacinghas created enough airflowaround the base of the plants to lower theriskofmoldandsufficientroomtopreventcompetitionforlight.

Oncetheplantsformacanopy,it isbestnottojostletheraftsorpullthemout to move them, particularly in the case of lettuce. Simply float themdownstreamwhen theyneed tobe rotated through the trough,according to theconveyor method. As the plants form a dense canopy, they becomeinterdependentforthephysicalsupportneededtostayupright.Ifamaturecropis thinned too late or jostledvigorously, theywill fall over andhave to spendtheirenergyoverthenextfewdaysturningbacktoanuprightposition.

PlantInspectionThereisverylittleongoingworkrequiredfortheplantsthemselvesduringtheirproductiontimeotherthaninspectionandcorrectingproblems.Theprimaryroleofanaquaponicfarmeristoensurethattheecosystemisfunctioningwithintheparameters specified in Chapter 6. Fluctuations in pH, water temperature,ammoniaandnitritesmustberemediedimmediately.

Plant inspection takes place via a quick daily check and amore thoroughweekly evaluation.Everyday,walkdown the aisles andobserve the rafts andSeedlingTable.Noticeanysymptomsofdiseaseornutrientdeficiency.Noticeleafdiscolorationorwilting.Noticeobvioussignsofpestsorswarmsofpests.Noticeanymoldormildew.Mostlynoticeanychangesfromthepreviousday.Ifyoumonitordaily,youwilllearntospotproblemsearly.

Weekly,dothesamebutmuchmoreclosely.Whereasyourdailyinspectionmaytakelessthanfiveminutes,yourweeklyinspectionmaytakeanhour.Scanthe rafts and seedling trays closely andbriefly lookat eachplant individually.Focus in on any symptoms. If you find a symptom, lookmore closely at theotherplantsinthatcropandparticularlyattheotherplantsofthesamevariety.Isthesymptomlocalizedtooneplant,orinonearea,ortoonevariety,orisitthroughout thecropor thewhole trough?Checksticky traps for signsofpestsandfocusonplantsinthoseareas.

SeeNutrientDeficiencieslaterthischapterandPestManagementinChapter10.

IMPORTANT

Aquickdailyinspectionandthoroughweeklyinspectionareyourbesttoolsforidentifyingnutrientdeficienciesandpreventingthespreadofpestsanddiseases.Withpracticeyouwillbeabletoquicklyidentifyandcorrectpotentialissuesbeforetheyspreadandbecomeaseriousproblem.

WateringintheGreenhouseThe greenhouse environment is not far removed from nature, with natural

sunlight and free airmovement, but it lacks one fundamental force of nature:rain.Rainprovidesmorebenefits tocrops than justwater. Itwashespestsanddustfromleaves.Itcandrownpests.Powderymildewfavorshumidconditionsbutonlygrowsondryleaves,anditssporesaresmotheredbywatertemporarilypoolingonleaves.Plantsalsoabsorbsomewaterbornenutrientsthroughleaves,particularlycalcium,potassiumandiron.

After considerable experimentation, we found that watering plants withwater from the troughs is as effective as botanical andbiological pesticides atkeepingmostpestanddiseaseproblemsincheck.Wateringisnotareplacementforpesticideuse,whichstillisrequiredonoccasion,butitworksverywellasaprophylacticmaintenanceprogram.Usingthispractice,wehavecutouruseofpesticidesby asmuch as 75%andonly require themwhen anoutbreak is notbeing effectively suppressed by a combination of watering, cultural andenvironmentalcontrols.

Watering with system water also provides nutrients directly to the leafsurfacesandhelpstoestablishahealthymicrobialecologyinthecrop.Astrongmicrobiome is thevery first lineofdefenseagainstbothaquaticand terrestrialpathogens. A healthy population of beneficial bacteria will outcompetepathogens and prevent them from establishing in sufficient numbers to causedisease.Asimilarprocessisatworkinyourdigestivetractandthebiofilterofyoursystem.

Ifyouwateryourplantswithsystemwater,werecommendrinsingproducewithpotablewaterbeforeselling.

Makingitraininthegreenhouse.

Inconsistentlyhotanddryseasons,werecommendwateringallplantstwiceperweek,inthemorningoreveningwhenthesunislessintense.Inthewinter,whenhumidityishighandwaterisslowertoevaporate,reducewateringtoonceperweekorlessandonlyinthemorningsothewatercanevaporateduringtheday.Itisimportanttoavoidhavingstandingwateronleafsurfacesforextendedperiodsoftimeasthiscanpromotemoldgrowthratherthanpreventitanditcansuffocatetheleaves.

Donotwatertheplantswithinthreedaysofsprayingapesticide,inordertoallow thepesticide towork.Also, if thepesticide ispotentiallyharmful to the

fish, the time will allow it to naturally degrade in the air and sunshine. SeeChapter10formoreinformationonpesticides.

To water the plants, place a small (~¹⁄₅ horsepower) oil-free submersiblepumpinthewaterneartheoutletendofoneofthetroughs.Attachagardenhoseandawateringwandwithadiffusertoformagentlespray.Usethissamepumpandnozzleforwateringtheseedlings.

One of the added benefits of growing inDWC troughs is that any excesswatersprayedontotheplantswilldrainbackintothetroughswithonlyasmallamount lost to evaporation. In a tower system,watering plants in thismannerwillwastelargequantitiesofsystemwater.

Harvest,PackagingandStorageHarvestingMethodsThe decision to harvest is based on a combination of your market and plantmaturity.Leafygreens(e.g.,lettuce)thatareleftgrowingpastmaturitywillstarttobolt(transitiontoproducingseed).Atthisstage,thequalitywillprogressivelydeteriorate as the plant quickly stretches upward and becomes very bitter.Conversely, youmay opt to harvest some plants prematurely to fulfillmarketdemand. If harvesting early, it may be appropriate to adjust the sales priceaccordingly. The decision of when to harvest is something you will learn toadapttoasyougettoknowyourfarmandyourmarketthroughtheseasons.

Theharvestingprocessvariesdependingonwhere/howyouselltheproductandwhetherplantsneedtobewashed.Wefindthatsomerestaurantswantdry,neverwashedheadlettucewhileothersonlywantwashedandbaggedmixes.Ifyouaresellinginbulkorwholesale,individualbaggingisnotusuallyrequired,butyoumayfinditpreferablewhensellingatafarmersmarket.

Most harvesting occurs at the troughs. We find this cleaner and moreefficient than carrying laden rafts to theworkbench. If you are producing thetypes of plantswe do for the same end products (heads of lettuce, saladmix,herbs and other preweighed produce), you will need at least four bins (totes)withyouatthetrough:oneforeachvarietyofstronglettucetobesoldasheads,one for “inglorious” plants to be processed into saladmixes, one for compostandonefornetpots.Weseparateourbinsintocleanbinsthatareonlyusedfor

produceanddirtyorolderbeat-upbins thatareonlyusedforcompostandnetpots.

Otherplants (onour farm,mustards andbabykale) that areharvested in acut-and-come-againstylemaybepreferabletoharvestbytakingtheentirerafttotheworkbench,whereitiseasiertopickoffindividualleaveswithoutremovingthe plant from the raft.Use separate totes for compost and net pots.Youwillneedseveraltotesforproductstobesold.

Dependingonwhatiscomfortableforyou,youmayharvestsomeorallofthepotswhiletheraftisinthetroughoryoumaypulltheraftpartiallyand/orfullyoutofthetroughasyouharvest.Experimentationisrequiredtofindwhatworksbestforyou.

Toharvestalettuceorotherhead-typeplant,pull thewholeplant—plant,netpotandroots—outoftheraft.Twistofftherootsthathangthroughthepotandputintothecompostbin.Separatethepotfromtherootball.Putthepotinthenetpotbin.Cuttherootballofftheplantandputitinthecompostbin.Byhand,removealldamagedoruglyouterleavesbypullingtheleafoutanddowntowards the base of the plant. Put all discard leaves in the compost bin. Putlettuce into a harvest bin, separating plants to be sold as heads and those formixes.

Insummer,headlettucedisplayedatafarmersmarketwilldryoutandwilt.This isunappealing tocustomersandwill result in fewersales.Tokeepheadsfresh,theycanbeharvestedandbaggedfullyintact,rootsandall,anddisplayedliveatthemarketinshallowbinswithabitofwaterinthebottom.

For live sales, remove the lettuce from the raft, leaving roots and net potintact.Removedamagedoruglyleavesthenputintoatotewith½″ofwaterinthe bottom, roots down. At the market, use shorter bins (with water in thebottom)todisplaythecrispheads.Whensold,leavetherootballattachedorcutoffdependingoncustomerpreference.Displayinglettucelikethisisabigdrawand is an excellent icebreaker for starting a conversation about the benefits ofaquaponicfarming.Inaddition,unsoldlettucecanoftenbeplacedbackintotherafts to continue growing, as long as care is taken to prevent damage duringhandlingandtransport.

Weoftensellbutterheadsaslivinglettuce,whichkeepforaverylongtime,even unrefrigerated. This is a value-added product which is often in high

demandandsells forapremium.Toharvesta living lettuce, twistandremovethehangingrootsandnetpotbutdonotcutofftherootball.Usethebottomofasmallplasticbagandanelasticbandtocontainthemoistrootball,thenpullthebaguparoundthelettuce,leavingtherosetteofleavesexposed.

Watercress,whenseededattherecommendedrate,willproduceathickmatofindividualshootsandleaveswithalayerofrootsspreadingacrossthetopofthe rafts. We find that cress does not regrow well in a cut-and-come-againharvest,so it ismoreeconomical to fullyharvestandreseed.Toharvestcress,pulloutanetpotandgentlytugtheshootstodisentanglethemfromtherestofthemass.Notice the smallwhite roots growing from the stems just above therootball.Leavingtheserootsoncangreatlyextendtheshelflife(1–2weeksvs5–6 days). If the cress is being sold by itself, cut the root ball low enough toleave someof these rootson.Placebunches inabinwith shootsand rootsallfacing in the same direction as this will make them easier to handle forportioningandpackaging.Ifthecressisdestinedforasaladmix,cutthebunchhigher(abovesmallwhiteroots)leavingonlyshootsandleaves.Seecolorphoto.

Removerootsbelowthenetpot.

Removethenetpot.Leaverootballintact.

Removedamagedleaves.

Wrapplasticbagaroundbaseoflettuce.

Useelasticbandtosecurebagaroundtherootball.

Freshlyharvestedlivingbutterlettuce.

Someplantscanbeharvestedmorethanonceusingthecut-and-come-againmethod.Weusethistechniquetoharvestmustardsandbabykaleintwoslightlydifferentways.Whenusingthismethod, try toavoid takingmorethan30%oftheplantatanyonetime.

Mustardstypicallyyield2–6harvestsbeforegrowthslows,dependingonthevariety.Theydon’ttendtoproduceathickcanopyofleaves,soitispossibletosniporcutindividualleavesfromaplantwithoutremovingthenetpotfromtheraft.Donotremovetheleafbybreakingitoffbyhand.Separateleavesintotwoharvesttotes:largerleavesforindividuallypackagedunitsandsmallerleavesforsaladmixes.Ifwehaveanexcessofmustards,weofferthemforsaleseparately,butwealwaysprioritizehavingsufficientsupplyformixes.

Babykalegrowsadensecanopyofleaveswhenseededattherecommendedrate and will also regrow vigorously enough to harvest 2 or 3 times. It is“mowed.” Without removing the individual net pots, cut all leaves off at arelativelyuniformheight,leavingaround2–4″ofplanttoregrow.Trytocutataheightthatwillharvestmostofthematureleaves,whileleavingthegrowingtipsatthecenterofeachshoot.In2–3weeks,theplantswillyieldanotherharvest.

Wesellromaineasfullheadsandhearts.Heartsaretheinnermostpartoftheplant.Dependingonmarketdemand,wetypicallyselllargerundamagedplantsasheadsandsmallerdamagedand/ordeformed“inglorious”plants,withouterleavesremoved,ashearts.Heartsaresoldinbagsof2or3(approximately1lb

totalperbag).Theyareofteninhighdemand,sellforapremium(thoughnotasmuchas thesamenumberofhealthy largeheads)andareanexcellentuse foringlorious plants that may otherwise be unsellable. Put heads and hearts inseparateharvesttotes.

IMPORTANT

Handleallplantsasgentlyaspossible.Stemsandleavesbreakandbruiseeasily,anddamagewillbecomemoreandmoreapparentastheharvestedplantsage.Whenfillingbins,donotoverfill,asthiswilldamageplantsatthebottom.

WashingPlantsSomeplantsmayneedtobewashed,dependingonthemarketandthequalityoftheplant.

Mostheadlettucewesellatafarmersmarketareunwashedunlesstheyhavemore than a few insects on them or were sprayed within two days prior toharvest.Oursaladmixesarealwayswashedtwiceanddriedbeforepackaging.

Oneofourregularrestaurantclientsinsiststhatlettuceremainunwashedtoextenditsshelflife.Theyprefertowashitthemselvesimmediatelybeforeuse.Wet produce will have a shorter shelf life unless the produce has ampleopportunitytodrybeforepackaging.

Washing your produce will remove bugs and dirt and can also help toreinvigorate plants that have wilted. If you are not using a walk-in cooler,washingyourproduceincoldwaterwillhelptochillitandextenditsshelflifepriortoshipping.

IMPORTANT

Ifyourproduceiswashed,onlyusefreshpotablewater.Neverusesystemwatertowashyourproducebeforesale.

Theeasiestmethodofwashingplantsistoplacetheloadedharvestbinsonthesumplidandfillthemwithpotablewateruntilallplantsaresubmerged.Letplantssoakfor5–10minutesbeforedraining.Thewaterusedforrinsingproducecanbedraineddirectly into the sumpso longas there areno leavesorbitsofplants.Wepourthewaterthroughapieceofwindowscreenasafilter.

Ifyouareattemptingtoreinvigoratewiltedheadlettuce,thebestwaytodothisistomakeafreshcutacrossthebaseoftheplant,wheretherootballwasremoved, and place the head in lukewarmwater. This will allow the plant toabsorbwaterfarmorequickly thanusingcoldwater.After15–20minutes, theheadsshouldlookfreshandcrunchyagain,readyforbinsorpackaging.

SaladMixesSalad mixes are always a big seller at a farmers market and often sell at apremium.Customersappreciatehavinga“readytoeat”option.Foranaquaponicfarmer,makingsaladmixesisagreatwaytosellingloriousplantsasapremiumproduct insteadofcomposting them.We typically findabout25%ofourheadlettuce are inglorious (less than ideal in size or presentation but still perfectlyedible).Alwaysrememberthateveningloriousheadscanstillhavegoodhearts.

Inorder tomakeagoodmix,varietyisrequired,not just lettuce.Wegrowvarieties ofmustards andwatercress specifically for adding to ourmixes.Ourmix is atypical, as it is “assembled” from various plants that are grownindividually.Most conventional saladmixesaregrownbybroadcast seedingavarietyofseeds together inonebedbeforemowingthecrop.Thismethodisaveryfastandeasywaytoproduceamixcomprisedentirelyofbabyleafgreens,butthefarmerhasnocontrolovertheamountofeachcomponent.Ourstyleof

salad mix is very well received, as it is always crunchy and robust with anexcellentshelflife.

We try to make our salad mix with approximately 50% lettuce (threevarieties) and the rest a varying mix of mustards, baby kale and watercress,dependingonwhat is available thatweek.After harvesting plants thatwill gointo themix, rinse them in their totes with potable water (not systemwater).Submerge the plants for 5–10minutes before draining, then store totes in thecooleruntilyouarereadytoassemblethemix.

Toassemblethemix,removetherequiredtotesfromthecoolerandstagethecomponents on the stainless steel counter/sink. In one single cut, remove thebase of each lettuce head and separate the leaves into clean bins.Discard anyleavesthataretoobigorbug-eaten(thiswillmostlybedonewhenharvesting).Assemble the components in clean bins in layers to minimize the need formixing,whichwillcausebruises.

Once a bin is full with amix, rinse a second time by filling the binwithpotablewater (not systemwater). Leave themix submerged for 5–10minutesbeforedrainingthewater.

Toensuremaximumshelflife,themixmusthaveasmuchwateraspossibleremovedpriortobagging.Useacommercialsaladspinner.Ifyoufindyouareprocessinglargevolumes(e.g.,morethan100lbsofmixeveryweek),thismaybecome an inefficient dryingmethod. Formore ideas on spinning and dryingsaladmix,werecommendconsultingTheUrbanFarmerbyCurtisStone(NewSocietyPublishers,2015).

Onceplantshavebeenharvestedandwashed(ifnecessary),youarereadytoportionandpackage.Alwayskeepproduceinthecoolerafterwashinguntilyouarereadytopackageit.

PortioningWhenportioningyourproducts,itisimportanttoconsiderthepriceofeachunitand your market. Certain products like salad mix and watercress are sold byweight,whereas others such as romaine hearts are sold by number. For somemarkets, itcanbeadvantageoustoofferasmallerandlargersizeofaproduct.Withsomepractice,youwillbeabletodeterminewhichsizesandpricesworkbestforeachproductandyourcustomers.

We typically portion salad mix in 5 oz. and 8 oz. bags, mustards andwatercressin6oz.bagsandromainehearts(3perpack)inapproximately1lb.bags.

PackagingWeuseavarietyofsizesofplasticbagsforallourpackaging.Therearemanyoptions that youmay prefer including corn-based eco-friendly composites andharder plastic clamshells that offer better protection from damage (great forlivingbutterlettuce).

Wholesale products usually don’t require packaging unless the buyer isretailing theproduct (wholesalersareusuallymiddlemen).Head lettucesoldatmarket doesn’t require bagging, although bags can be effective to protect theheadsandtohelppreventdryingoutonhotdays.Weprefertodisplaythemliveinwater.Manycustomerswillrequestabag.

Wehavefoundthatcertainproductsneedtobebaggedjusttopreventthemfromdryingouteveninmildweather.Theseincludewatercress,saladmixandmustards.Leavebagsofcressandmustardsopenandfoldeddowntocreateanattractivedisplay(aslongastheydon’twilt).

Bagsofsaladmixmustbesealedtoensurealongshelflife.Oncealettuceiscut, theexposedcutwillundergoenzymaticoxidationwhich turns thebaseofthe leaf an unattractive brown. This is the same process that occurs when anappleiscut.Itisharmlessbutunattractiveandthereforeundesirable.Enzymaticbrowning can be delayed by chilling the product to slow the reaction and bysealingtheproductinabagtoreduceavailableoxygen.

Bagscanbesealedwithtwisttiesorelasticbands,butwehighlyrecommendusingatapebanderwhichisfasterandmoreeconomical.

Aplasticbagbandersealsandtrimsthebag.

HarvestCleanupHarvestcleanup isasimple joband takesplaceafterharvest.Moveall freshlyharvested(empty)raftsoutsideforcleaningandplaceblankrafts(withnoholes)intothetroughs.Itisimportanttonotleavetroughsexposedtosunlightformorethanafewhoursasthiswilldestroythebiofilmonthelinerandencouragethegrowthofalgae.Werecommendhavingblankrafts(withoutholes)onhandforthispurpose.Ifyoudon’thaveblanks,putcleanedraftsbackinwithemptynetpotstoreducelightpenetration.

Useahosewithastrongnozzletorinseoffbothsidesoftherafts.Aquickrinsewillusuallysuffice to remove thedebris—mainlydead leavesandcropresidue—thathascollectedon the top. Ifneeded,gentlyscrub the topwithasoft bristle brush. If therewasmold ormildew present in the harvested crop,sterilizethetopoftheraftwithaweakvinegarorhydrogenperoxidesolutionof3–5ml/L.Ifusingvinegar,rinseraftswelltopreventitfromenteringthesystemwater.Stackraftsforreplanting.Becarefultonotbringinoutsidedebrisonthe

rafts.

IMPORTANT

Neverscrubthebiofilmontheundersideoftherafts.Asprayfromthehoseshouldsufficetoremoveanydebris.Thisfilmispartofthebiofilter.

Raftcleaningtools:hosewithnozzleandsoftbristlebrush.

Netpotsneedtobewashedbetweencropstoremoverootsanddebrisandtosterilize them if therewasmold present.We recommend installing awashingmachine outside the greenhouse for this purpose.Ours is located on the northsideofthecooler,westoftheGerminationChamber.Washthepotsonagentle

1.2.3.4.5.6.

cycle using a small amount of non-toxic, biodegradable, unscented soap, orhydrogen peroxide if sterilizing for mold (15 mL of 30% per liter). Aftercleaning, nest thepots and store them in a cleanbinuntil they areneeded fortransplanting.

TheProductionCycleSofarinthischapterwehavedescribedthelifeofaplantfromseedtoharvest.Inoperationalreality(fromtheperspectiveofthefarmer),theentireproductioncyclehappensinreverseorder.

Your objective is to be operating at full capacity at all times: fullGermination Chamber, Seedling Table and troughs. Once the system is atcapacity,thefirststepintheproductioncycleisharvest.Harvestcreatesroominthetroughsforseedlingstobetransplanted,whichcreatesroomontheSeedlingTablefornewsprouts,whichcreatesroomintheGerminationChamberfornewseeds.

Theproductioncyclemustbeconductedinthisorder:

Harvest(includingcleanup).Thinningandspacing.Rearrangingrafts(conveyorcropping).TransplantfromSeedlingTabletoraftsanddirectseeding.MovetraysfromGerminationChambertoSeedlingTable.PlantnewseedsintoGerminationChamber.

NutrientDeficienciesIdentifyingdeficientnutrientsisabitofanart.Withsomeexperience,itwillbesecond nature. As with pest and disease management, your daily and weeklyinspections are the primary diagnostic tool.Water testing for nutrient contentwilloftenfurtherclarifythedeficiency.

Inthecolorphotosectionof thisbook,youwillfindaNutrientDeficiencyKey (created byBrightAgrotech; usedwith permission). There are numeroussimilarkeys,butthisisthebestonewehaveseen.Followthestep-by-stepflow

to determine the deficiency. Additional copies of the key are available fromBrightAgrotechviatheirwebsite.

To resolve specific deficiencies, take the following actions. With anycorrective action, run the appropriate chemical test(s) regularly afterwards togaugetheresult.

NitrogenYou should never have a lack of nitrates. Aquaponic systems produce largequantitiesofnitratesastheprimarymineral.

Nitrogen deficiency shows as chlorosis (yellowing) across entire leaves.Notethatsomeyellowingontheoldest,biggestleavescanbenormalandshouldnotimmediatelybeassumedtobeanitrogendeficiently.

Nitrogen deficiency is caused by low feed input. Gradually increase thequantityoffeed,testregularlyforammoniaandnitritestoconfirmthebiofilterisnotoverwhelmed.

CalciumandPotassiumCalcium and potassium (along with iron) are the most commonly deficientmineralsinourexperience.Calciumandpotassiummustberelativelybalanced.An excess of either can cause the other to be locked out (not available foruptake).

IMPORTANT

Thedeficiencysymptomsforbothcalciumandpotassiumcanlookverysimilartoeachotherandcanlooksimilartocertaintypesofpestdamage.Ifyoufeeloneisdeficient,runchemicalteststoconfirmthereisadeficiency.Don’ttakeactionbeforetestingasyoumayaddtotheproblem.

Calciumlevelswillvarygreatlydependingonyoursourceofwater(wehavevery soft water with very low calcium). Sustained high humidity levels (over80%)canalsopreventcalciumuptakedue todecreasedplant transpiration.To

increasethecalciumlevel,agitate theCFBsockmorevigorouslyand/ormorefrequently.Increasesockuseverygradually.

YoucanalsosupplementcalciumbyusinganorganicCal-Magsolutionasafoliar spray. There are numerous products available. We use Botanicare Cal-Mag+.

ThemostcommoncauseofpotassiumdeficiencyisalackofbalanceinpHmanagement. You are likely shaking the sock too hard and/or often, whichmeansthepHdosingcontrollerisnotinputtingpotassiumhydroxideatsufficientlevels.Toremedy,ceasesockshaking.Testdailyandrecommencesockshakinglessfrequentlyand/oraggressivelyoncethetwolevelsarebalanced.

IronIronwillbelackinginalmostallaquaponicsystems.Itisnotcontainedinlargeamounts in the feed and will not likely be present in your source water in ausable form. Iron is highly reactive in aerobic environments and tends tocombine with other molecules, becoming unavailable for absorption by theplants.ThisislessofanissueatalowerpH,abenefitofoperatingthesystematthe recommendedpHof6.5. Iron is avitalmineral forplantgrowth andyourplants will almost certainly require more than is found in the water withoutsupplementation.

In an aquaponic system, iron is usually present in two forms: ferrous iron(Fe2+)whichissolubleinwaterandavailabletotheplants,andferriciron(Fe3+)whichisinsolubleinwaterandunavailabletotheplants.Rust,orironoxide,isferric(insoluble)andshouldneverbeadded.

Werecommendsupplementingironmonthlywith2–3ppmofahigh-qualitychelatediron,whetheryourplantsshowsignsofdeficiencyornot.Chelatedironisferric(insoluble)ironthathasbeenboundtoanorganicmoleculetomakeitsolubleandthusavailabletoplants.ThethreemostcommonformsofchelatedironareFeEDTA,FeEDDHAandFeDTPA.

UseonlyFeDTPAas theother two are either slightly toxicor ineffectivebelowapHof7.0.WerecommendAmazonIronfromTailoredAquatics.

Ifanirondeficiencyoccurs,graduallyincreasethefrequencyofinput.

HighAmmonia

AfinalnotethatisnotincludedintheNutrientKey:asignofahighammonialevelcanbeawhiteresiduethatlookssimilartomineralscalearoundtheouteredges of leaves. If you spot this symptom, do a chemical test for ammoniaimmediately. If the test confirms elevated ammonia, reduce or eliminate feeduntilthebiofiltercatchesup.

T

PlantDiseasesandPests

HEREARENUMEROUSDISEASES AND PESTS thatmay impact your plants.WewilldiscussthosewehavefoundtobemostcommoninourDWCsystem.

Pythiumdamagedplant(middle).Thefirstsymptomisoftenawiltedplantsurroundedbyhealthyplants.

PythiumPythium is the most common and persistent pathogen we encounter. It is anopportunisticfungithattakesadvantageofplantsweakenedbyheat,lowoxygenorpestdamage,causingadiseaseknownas“stemrot,”“rootrot”or“dampingoff.”

Pythiumsporesexistnearlyeverywhereinsoilandwaterbutdonottypicallyattackplantsunlessplantsarestressedorthereisphysicaldamage.Fungusgnatsareknowncarriersofpythiumspores, and their larvaecanspread infectionbyfeedingonroots.Onceinsidetheplant,pythiumfeedsontissueandeventuallyreleasessporesbackintothesystemtospreadandinfectotherplants.

Typically, the first observable symptom of a pythium infection is poorgrowthorwiltingfornoapparentreason.Uponcloserinspection,theplantwillusuallyhavearottenbrownstemandinadvancedcaseswillseparatefromtherootballwhenlifted.

Pythiumprefersdark,wetanaerobiczones.Placingoneairstoneundereachraft per our design will greatly reduce the potential for anaerobic zones nearplantroots.PythiumsporesarealsodestroyedbyUVdosesintherangeof30–40 mJ/cm2, well within the sterilizing capabilities of the recommended UVsystem.

Pythiumdamagecausesstemrot.Theheadofthislettuceisfullyseparatedfromtherootball.

Inspectionandearlyremovalistheprimarymanagementmethod,alongwithplantingonlyhealthy,vigorousseedlings.Oxygen-saturatedwaterandlowerairhumidityarealsobeneficial,asiswateringplantswithsystemwaterasdescribedinChapter9.

Ifpythiumisrampantandsprayingisrequired,useabio-fungicideproductsuchasNatriawhichisnon-toxictofishandOMRIlisted.Spraysshouldonlybe used as a last resort in cases of severe infection. See Pesticides andFungicideslaterinthischapter.

Powderymildew.

PowderyMildewPowderyMildew(PM)isafungaldiseasethataffectsawiderangeofplantsandiscommoningreenhouses.Itiseasilyidentified:itlookslikeathickcoatingoficingsugar.Itoftenstartsassmallcircularoutbreaksbeforespreadingacrossaleaf or stem. PM can be a problem at almost any time of year, depending onlocalconditions.

The primary management method is environmental control to preventconditions which encourage PM growth, and inspection and early removal ofinfected plants. Healthy plants, inspection and early removal are the first andbestremedies.Carefullyremoveplantsfromthegreenhouse,takingcarenottospreadsporesandmovetocompost.

Thepowderthatisvisibleonaplantisonlythefruitingsectionofthefunguswhich penetrates the leaves.Once a plant is infected, the PM cannot be fullyremovedwithouttoxicsystemicpesticides,buttherecommendedtreatmentwillpreventitfromspreadingtootherplants.

PMcanbetreatedbysprayinghighpHwater(9.0–10.0)with3mLof30%hydrogen peroxide per liter. Note that higher concentrations of peroxide willburnorwhitenplant leaves.BothhighpHwaterandH2O2combatPMand insmallquantitiescanbeusedwithoutconcernforyourfish.ApplicationsofhighpHwater with H2O2 may be required every 2–3 days as new fruiting bodiesemerge.

Somefungicides,suchasNatria,specifythattheyareeffectiveagainstPM,but as with the H2O2 spray, it only destroys the fruiting body and not themyceliumwhichpenetratestheleaftissue.HighpHwaterwithH2O2isthebestoptionifsprayingisrequired.

Some seed producers are now offering seeds that are resistant to PM viaselectivebreeding.Werecommendsuchseedsiftheyareavailable.

FungusGnatsFungusgnatsareacommonpestinalmostallgreenhouses.Intheiradultform,theylooklikeverysmallmosquitoesthathoverinswarms1–2′abovetheplantcanopy.Theylaytheireggsinthesoilaroundaplant′sbase.Theresultinglarvaelook like small (1–5mm)whitewormswith black heads. The larvae feed onplantrootsuntiltheypupateandflyabovethecanopy.

Thedestructionofrootsistypicallynotabigproblemaslongasplantsarehealthyandvigorousandthegnatpopulationisnotextreme.Thebiggerproblemisthatgnatscanalsocarryandtransferpythium,whichisfarmoredangerous.

Gnatsareverydifficulttoeradicate.Limitingtheirpresenceshouldbeyourgoal. The most effective control is planting only strong, vigorous seedlings.Strongplantswilloutgrowdirectgnatdamageandwillgreatlyminimizetheillsofpythium.

Therearenumerousbiologicalcontrols thatareeffective inkillinggnats inthelarvalstageviaapplicationtothesoil.However,duetothesmallsoilcontentandconstantsoilwetnessinaDWCsystem,suchcontrolsarenotveryeffectiveandlikelynotworthconsidering.Similarly,usingapesticidesprayorfogtokilladults on contact in the air is only temporarily effective as the larvae remainunharmed.Spraysshouldbeusedwithcautionandonlyinextremecases.

Aphids

Mostcommoninhotterseasons,aphidsareanotherubiquitousgreenhousepest.Typically limegreenorbrown,aphids resideonplant leavesandshedawhitehusk. Both pest and husk are easy to identify. They spread very quickly anddon’tdoalotofdamageunlesspresentinveryhighnumbers.

Aphids.

Thebiggestproblemwithaphids isnotnecessarily thedamagetheydobuttheir impact on sales: customers do not like to see aphids on plants, andrestaurantsdon’tlikehavingtowashproducemultipletimestoremovethem.

Options for aphidmanagement includewashing them off and/or drowningthembysprayingplantswithsystemwater,sprinklingdiatomaceousearthontheplantstodessicatetheaphids,andusingapesticidespray.Asalways,pesticidesshouldbeusedwithcautiononlyinextremecases.

Ifyoufindgroupsofaphidsonyourplantsatharvest,theycanalsosimplybewashedoff.Itmaytaketwoormorerinses.Aphidsdieoffnaturallyincolderseasons.

CabbageLoopers

Loopersaresmallgreeninch-wormpeststhataretypicallylessthan1cmlongandhaveavoraciousappetite.Theyaremostlynocturnal feedersandcan ruinmultipleplantsovernight.The first signof loopers is typically apatchworkofholesinleavesaccompaniedbylargequantitiesofsmallgreenballsoffeces.

Loopers are bestmanagedvia the same controls as aphids: direct sprayingwithsystemwater,sprinklingdiatomaceousearthor,asalastresort,afish-safepesticide.

EarwigsEarwigs prefer decaying organic material but will also feed on tender lettuceleaves, chewing small holes similar to loopers. Earwigs are nocturnal feedersthatdolessleafdamagethanloopers.Theynestinthebaseofaplant,makingthem hard to see on casual inspection. Visual indicators of an infestation aresmallholeschewedinleavesaccompaniedbynecroticpatchesontipsofleavesonwhichthebugshavelaideggsatthebase.

Ourexperienceisthatearwigspreferaplantthatlayersitsleavesandformsa protective shelter for the bug. Romaine and butter lettuce seem to be theirfavorites.

Leftunchecked,earwigswillquicklyspreadanddamageplantstothepointwhere they are no longer marketable. Inspection and early removal is key tomanaging them. Use diatomaceous earth to control outbreaks and, as a lastresort,afish-safepesticide.

Earwig.

PillBugsPillbugsareactuallycrustaceans(likelobsters)andbreathewithgillsinsteadoflungs. They prefer very damp and dark locations and are nocturnal feeders.Likelyfoundinandaroundthenetpots,theytypicallyeatdecayingleavesandroot tissuesbutwill occasionally eat tender seedlingsoryoung leaves that aretouching the ground. Damage from pill bugs is usuallyminimal and they aretypicallyonlydetrimentaltomarketappeal.

As always, inspection and early removal is key to keeping them undercontrol. Outbreaks can be controlled with applications of diatomaceous earthand,asalastresort,afish-safepesticide.

SlugsSlugs are a fact of life for any humid, moist or wet plant growing space,includingallgreenhouses.Theyarebestmanagedinsmallnumbersbymanuallyremovinganddrowningthem.

Beer traps, coffee grounds and copper are all purported to be natural

solutions,butwehavefoundnoneofthesetobeevenmoderatelyeffective.Wehavewatchedthemdrinkthebeerandmoveon,slideovercoffeegrounds,andshownosignofrepulsionwhentheyencountercopperwireortape.

Crushed oyster shells or diatomaceous earth, commonly available in largebagsforminimalcost,aremoderatelyeffectiveasaphysicalbarrieriflaidinanunbrokenringaroundthetroughs.Thisdoesn’tkillslugsbutprovidesabarrierduetosharpedges.Asalastresort,ironphosphatebaitpelletscanbeusedwithcaution.

BirdsGreenhouses can be ideal refuges, playgrounds and nesting areas for birds. Insummerwhenthewallsanddoorsremainopen,thegreenhousecanactasahugeflyinginsecttrap,andbirdslovetotakeadvantageoftheeasybuffet.Inwinterwhenfoodandwarmtharescarce,birdswilltakeupresidenceandeatanynewlygerminatedseedsthatareleftuncovered.Unfortunately,despitetheirbenefitsasinsecteaters,birdsshouldbediscouragedfromenteringthegreenhouseastheytendtoleavedroppingsonthecrops.Asmuchaswelovebirds,wechasethemoutusingafishingnetbeforetheygetusedtoinhabitingthespace.

In summerwhen the roll-up sides are left open, birds can be excluded bysecuringshadeclothorothermeshscreenacrosstheopening.

RatsRats can destroywhole trays of young seedlings rapidly, like a drive-throughsaladbar.Additionally, rat feces is tobe avoideddue tohealth risks.Rats areprimarily attracted to the smell of the fish feed and will make themselves athome if they can access it.Keepyour fish feed safely locked in vermin-proofstorageandtakecarenottospillpelletsonthegroundwhenfeeding.

Adeadminkandourfarmdog,Tango,defenderoftrout.

Manageratswithtrapsand/orafarmdog.Bemindfulofwhereyoulaytrapstoavoidinjurytoworkers,childrenandpets.Donotuseratpoison.Poisonhasnoplaceinornearanaquaponicsystem.

MinkandMartenMink,martenandothersemi-aquaticmammals in theweasel familymayviewyourfarmasarestaurant.Attractedbythesmell,theywilldiveintoatankandkillnumerousfishbeforetakingjustone.Minkareparticularlyfearlessandwillnotbedeterredbyhumanactivityalone.

Theeasiestcontrolisthepresenceofafarmdogforwhomhuntingminkandother small mammals will be a desirable job. Live traps are effective whenbaitedwithfreshfish,thoughyoumustthenrelocatetheanimal.Ifalethaltrapisused,bemindfulofchildrenandpets.Donotusepoison.

BearsBears are not common in our experience despite living in an areawhere theyroam.Asopposedtomink,bearsareusuallyverywaryofhumans.Thelights,

sound and human activity of an aquaponic farmwill usually keep all but themostdesperatebearsaway.Itisbeyondourcapacitytoprovidesafeinstructionforanencounterwithabear.Ifyouhavemanybearsinyourareaorareworriedaboutabearencounter,researchyourplanofactionwithabearexpert.

PlantDiseaseandPestManagementPlantdiseaseandpestmanagementoptionsarevery restricted inanaquaponicsystem due to its biological complexity and interconnectivity. A varyingpercentageof anychemicalor substanceusedwill endup in the systemwaterandcaneasilybetoxictothefish.

IMPORTANT

Pesticidesandfungicides,eventhosethatarederivedfromnaturalorbotanicalsourcesandthosethatareOMRIlisted,maybetoxictoyourfishevenifconsideredsafeforhumansorotheranimals.Extremecautionmustbeusedwithanysubstancesprayedorotherwiseappliedonoraroundyourplants.

We highly recommend learning and implementing Integrated PestManagement (IPM) protocols. The United Nations Food and AgricultureOrganization defines IPM as “the careful consideration of all available pestcontrol techniques and subsequent integration of appropriate measures thatdiscourage the development of pest populations and keep pesticides and otherinterventions to levels that are economically justified and reduce orminimizerisks to human health and the environment. IPM emphasizes the growth of ahealthy crop with the least possible disruption to agro-ecosystems andencouragesnaturalpestcontrolmechanisms.”

Thefirstandbestlinesofdefenseagainstpestsanddiseaseareculturalandenvironmentalcontrols.Wecannotoverstatetheirimportanceinpreventingandminimizingdiseaseandpests.

CulturalControlsCultural controls are practices that reduce pest establishment, reproduction,dispersalandsurvival.Themostbasicandimportantculturalcontrolisthedailyandweekly plant inspection. Diseased or pest-infested plants should removedfrom the facility immediately. Sterilize your hands after removing plants topreventthespreadofdisease.

Plantqualityandmaintenanceisalsoaculturalcontrol.Ifaparticularplanttypedoesnotdowellinyoursystem,donotgrowit.Inanaquaponicfarm,theplantmustmatchthesystem,notviceversa.

Everyweek youwill germinatemore seeds than youwill require, for oneprimary reason: so thatyoualwayshavehealthy, strong,vigorous seedlings totransplant into the troughs.Donot transplantweakseedlings.Thinningand/orspacingplantssotheyarenotcrowded,stressedandstretchingforlighthelpstokeepplantsstrong.

IMPORTANT

Itisoftenbetternottoplantafullcropthantoplantweakseedlingsthatcanleadtodiseaseorpestoutbreaksthatmayalsoinfectothercrops.Morethananyothersinglefactor,havingstrongplantsandahealthyecosystemisyourbestdefenseagainstdiseaseandpests.

Inhotter/drierseasons,itisbeneficialtosprayplantsviayourdiffusedwaterwandwithsystemwateronceortwiceaweek.Thisassistsinwashingoffpestsand acts as a foliar feed which can be particularly useful for calcium andpotassiumuptake.

EnvironmentalControlsEnvironmental controls are the conditions of your greenhouse: air and watertemperature, humidity, light level and air movement. In order to have strongplants,youmusthaveagoodenvironment.

Watertemperatureshouldbeautomaticallycontrolledbytheheatpumpand

1.

2.

3.

4.

keptataconsistent15–17°C(59–63°F)allyear round.Air temperatureshouldneverdropbelow5°C(41°F) includingatnight.Set thepropaneheater to turnon at 5°C; place the thermostat as near to the plant canopy as possible. Airtemperature less than 7°C (45°F)will greatly reduce pest populations: fungusgnats,aphidsandearwigswilldieofforhibernate.Airtemperatureabove25°C(77°F) should be reduced via passive and/or powered ventilation and/or shadecloth.

In cold seasons, use circulation fans to equalize temperature and humiditythroughoutthegreenhouse.Inwarmseasons,thesefansshouldbeturnedofftoallowtheairtostratify.Withthefansoff,warmairwillrisetotheroofwhereitcanbeventedout,drawingcoolerairinthroughthedoorsandroll-upsides.

For optimum plant growth, humidity should be 50–80% year-round.Hygrometersareinexpensiveandcommonlyavailable.Placethemneartheplantcanopy in various locations as well as outside. PM and most other fungaldiseasesthriveinhighhumidity.Severeoutbreakscanbepreventedbyloweringthe humidity: increase air movement via circulation fans and/or increaseventilation via roll-up sides or peak vents. Large dehumidifiers designed forgreenhousesareeffectivebutdrawhugeamountsofelectricity.

Heating/VentilationCycleInwinter,iftheoutsidehumidityislowerthaninsidethegreenhouse(whichisnearly all the time), humidity can be lowered manually with an activeheating/ventilationcycle.

Usethepropaneheatertotemporarilyincreasethetemperatureby5degreesorso.(Warmairholdsmoremoisturethancoolair.)Wait at least 15 minutes for the air to circulate and absorb moisture viacirculationfans,thenturnofftheheaterandfans.Turnon thepowerventilation system tovent thewarmmoist air.Monitortemperatureandhumiditythroughoutthecycle.Oncehumidityhasdropped, turn theventilation systemoff andcirculationfansbackon.Resetthepropaneheatertoengageat5°C.

This cycle is most effective at dawn and dusk when humidity in thegreenhouse tends to be the highest. A few cycles may be needed to lower

humiditytoacceptablelevels.Theonlydrawbackisusingadditionalpropane.

Yellowstickytraps.

StickyTrapsSticky trapsarecheap,brightyellowpapercardscovered inastickyresin thatare very useful in helping to identify early stages of pest infestation. Werecommendhangingthemjustabovethecanopyatrandomlocationstoidentifywhenandwhereapestpopulationisgrowing,byobservingtheconcentrationoftrappedinsectsoneachcard.

PredatoryInsectsPredatory insects targetpest species.Acommonexample isusing ladybugs tocontrol aphid populations. We have experimented with numerous predatoryinsects and found them to be helpful but not capable of resolvingmajor pestissues. They can also be quite expensive. Predatory insects are best used inclosed greenhouses (when the sides are closed) to combat low-level pestinfestations.Wehavefoundthemtobeineffectiveinmajoroutbreaks.

UsingPesticideandFungicideSpraysTheterm“pesticide”ismuchmalignedandoftenmisunderstood.Apesticideisany substance used for destroying insects or other organisms harmful tocultivated plants or animals. These include synthetic chemicals as well asnaturallyderivedcompoundsandminerals, botanically sourced substances andeven biological pesticides which contain organisms that are pathogenic to thetargetpest.ManypesticidesandfungicidesareOMRIlistedorapprovedforusein organic production because they are considered safe for humans and havelittlenegativeeffectonanaturalenvironmentwhenusedasspecified.

Pesticide use in an aquaponic greenhouse is inevitable, as cultural andenvironmental controls won’t resolve severe pest outbreaks and commercialgrowers do not have the luxury of experimenting with marginally effectivehomemade remedies. Only pesticides that are OMRI listed or allowed underorganiccertificationstandardsshouldbeconsidered.

Onecommonlyusedbotanicalpesticideapprovedfororganicproduction ispyrethrins.Derivedfromthechrysanthemumplant,itishighlyeffectiveagainstmanycommonpests, includingfungusgnats,aphids, loopersandearwigs. It isalsohighly toxic to fish.Substancessuchaspyrethrins shouldonlybeused inthemostextremeoutbreakswhenallothermethodshavefailedandonlyif theleveloftoxicitytothefishiscalculatedandamaximumapplicationlimitstrictlyadheredto.

IMPORTANT

Apesticidethatisconsideredsafeforhumanconsumptionisnotnecessarilysafeforfish.

LethalConcentrationCalculationBeforeusinganysubstanceasaplantspray,youmustfirstdeterminewhetheritistoxictoyourfishand,ifso,whetheritcanbeappliedinamannerthatissafe

1.

for the fish, yet still effective. All pesticides and many other chemicals andagricultural products have been tested on a variety of organisms to determinetheirpotentialtoxicity,whichisquantifiedasthelethalconcentration(LC50)orlethaldose(LD50)

Generally, theLC50 is theconcentration (inwater)ofa substance thatwillkillhalfofthetestedspeciesoveraperiodoftime(usually96hours).However,it isnotanexact sciencebecause therearemany factors that canaggravateormitigate the toxicityofa substance, including theamountofdilutedspray thatactually enters the water, the length of exposure time, the substance’s rate ofdecomposition,watertemperatureandpH.

DeterminetheLC50of thesubstancefortrout(oryourchosenfishspecies)usingtheMSDSoftheproduct,themanufacturer’swebsiteoronlineresourcessuchasthePesticidePropertiesDatabase.

IMPORTANT

Itisouropinionthatapesticideshouldonlybeconsideredforuseinyouraquaponicsystemifyoucanbecertainthatlessthan10%oftheLC50ofasubstancewillmakeitswayintothewater.

TocalculatetheLC50foryoursystem,youwillneedtoknowtheamountofactiveingredientinthepesticide,theLC50oftheactiveingredientfortrout(oryour chosen species), the volume of water in the system and the amount ofdilutedspraythatisneededtoprovideeffectivecoverage.

The following is an example of aLC50 calculation for the pyrethrin-basedproduct Pyganic™. This is for demonstration purposes only. We recommendyou seek the advice of a pesticide professional prior to using any pesticide orfungicide.

Multiply thevolumeofwater in thesystembytheLC50of thepesticide tofindtheLC50valueforthesystem.ThePesticidePropertiesDatabasestates

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thattheLC50ofpyrethrinsforrainbowtroutis.005mg/L,therefore:

(systemvolume)×(LC50)=LC50ofthepesticide

(66,000liters)×(.005mg/L)=330mgor0.33mL

Forasystemthatcontains66,000Lofwater,theLC50ofpyrethrinis0.33mL.Thisshowsjusthowtoxicpyrethrinsaretofish.

Pyganic™contains1.4%pyrethrins.TheLC50forPyganic™inyoursystemistherefore:

(LC50ofthepyrethrinsinyoursystem)/(concentrationoftheproduct)=

LC50ofproduct

(0.33mL)/(0.014)=23.5mLofPyganic™

Pyganic™recommendsadilutionof1–2ouncespergallonofwater(7.5–15mL/L)whichwouldseemtoallowonly3Loftotaldilutedspray(at7.5mL/L),yieldingatotalpyrethrinsloadof0.315mL,toreachLC50.

Itisouropinionthatapesticideshouldonlybeconsideredforuseifyoucanbecertainthatlessthan10%oftheLC50ofthepesticidewillmakeitsway into thewater. In thisexample, thatwouldmean less than160mLofmixed spray at the highest concentration or 320 mL at the lowestconcentration.

Weknowfromexperiencethat,usedcautiouslyandproperly,upto8LofPyganic™canbe safelyused inourdesignat7.5mL/L,asoftenaseveryfourdays,withnoharmtofish,duetoseveralmitigatingfactors,andthat8Lofsprayisapproximatelysufficienttocoverthegreenhouse.

Determine the amount of active ingredient thatwouldbe in the volumeofdiluted spray required for effective coverage.Assuming you require 8L ofdiluted pesticide to spray the entire greenhouse with Pyganic™ at therecommendedconcentrationof7.5–15mLperL:

(15mLperL)×(8Lofspray)=20mLofPyganic™,whichcontains:

(120mL)×(1.4%concentration)=1.68mLofpyrethrins

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3.

From thiswe can see that 8Lofmixed spray at the highest applicationrate contains five times the LC50 of pyrethrins. Even using the lowestapplicationrateof7.5mL/L,itwouldstillcontain2.5timestheLC50.

Pesticide infiltration can potentially be problematic in DWC systems, asrunoff from the plants can easilymake itsway between the rafts and into thewater. For all pesticides and fungicides, it is imperative to avoid spraying theplants to the point of runoff. Applying the spray with a fogger and using aspreader/stickeradditivewillalsogreatlyreducerunoff.

There are also other influencing factors that may mitigate toxicity.Remember that the median lethal concentration for trout is .005 ml/L for adurationof96hours(4days).Whenexposedtowaterandsunlight,pyrethrinsdegrade rapidly, having a half-life of 12 hours. This means that 50% of thepyrethrins will have decomposed 12 hours after application, and 50% of theremainder in another 12 hours, and so on. TheUV sterilizersmay also be ofsomebenefitinthiscase,aspyrethrinsarerapidlyphotolysedbyUVlightinthepresenceofwater.

IMPORTANT

Wedonotspecificallyrecommendtheuseofpyrethrinsoranypesticideorfungicide.ThissectiondemonstrateshowanOMRIlistedpesticidethatisconsidered“safeforhumans”canbetoxictoyourfish.Alwaysconsultapesticideprofessionalpriortousinganypesticideorfungicide.

Ifyoudochoosetouseanypesticideorfungicide,beextremelycautiousandfollowthesestepstopreventthesprayfromenteringthewater:

Useafoggerratherthanasprayer.Addaspreaderadditivewhichwilldecreasethesurfacetensionofthesprayandpreventtheformationoflargedropletsontheleafsurfaces.Donotsprayplantstothepointofrunoff.Thisisvital.

4. Forthreedaysafterspraying,donotwaterplantswithsystemwater,asthiswillwashpesticidesintothesystem.Thisisalsovital.

Alwaysreadandfollowallinformationontheproductlabel.Inmanyplaces,it isagainst the law touseapesticide inanywayother thanasdirected.Onlysprayduringthemorningorevening,neverinfullsunlight.Manychemicalscanbephytotoxictoplantsifappliedinheatorintensesunlight.

IMPORTANT

AlwaysreadtheMSDSofthespecificproductyouplantouse.Rememberthatthetoxicitytofishislikelynotconsidered.Payattentionto“inactiveingredients”whichmayalsobetoxictofish.Ensurethepesticideislegaltouseoncommercialfoodcrops.

Tableshowingpesticideswehavefoundtobeeffectiveonourfarm.

Re-entryIntervalThere-entryintervalistheminimumlengthoftimethatmustpassbetweenthetimeapesticidewasappliedtoanareaorcropandthetimethatpeoplecangointo thatareawithoutprotectiveclothingandequipment.Everypesticidehasare-entryintervallistedonthelabelthatmustbefollowed.

PersonalProtectiveEquipment(PPE)PPEmustbewornanytimeyouarespraying,evenif theproduct isconsideredsafeforhumans.Many“safe”pesticidescanstillcauseirritationtoskinorlungs.Arespiratoriscrucialforprotectingyourself.

PPEforsprayingpesticidesinthegreenhouseinclude:

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TallbootsorshoeswithsocksLongpantsthatcovertheanklesLong-sleeveshirtbuttoneduptotheneckNitrileorotherchemicalresistantglovesAhatorhoodandfaceshieldorgogglesArespirator

A set of chemical-resistant overalls are recommended as they offer moreprotectionthanclothingandcanbewornoveryourworkclothes.

FoggersFoggersputoutanatomizedmistratherthanasmallsprayofdroplets.Thefinemistcreatedbyafoggerisfarlesslikelytoformdropletswhichcanfallpastoroff leaves.This isvital tominimizingrunoff.Werecommendusinganelectricfoggerrather thanapressurizedsprayer.Therearenumerous typesandqualityoffoggers.WerecommendHudsonfogatomizers.

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StandardOperatingProceduresandProtocols

HISCHAPTERCONTAINSOURTRIEDANDTESTEDStandardOperatingProcedures(SOPs),logsandprotocolstoruntheRCAsystem.Mostofthedetailsfor

eachtaskhavebeencoveredearlierinthebook.Thepurposeofthischapteristodetailwhenandatwhatfrequencyeachtaskisperformed.

Recreateeachlogandprotocolandkeepinthegreenhouse,withlogstobecheckedoffor filled inas theyarecompleted.Keepa file forcompleted logs.Thisrecordofactivityisstandardgoodpracticeandwillallowyoutoexaminethehistoryofyourfarm.

Samplelogsandprotocolsareattheendofthechapter.Formattedblanklogsareavailableonourwebsite.

Thischaptercontains:

DailyLogWeeklyTasks(Phases1–4)WeeklySeedingChartCropLogFishSampleLogCohortLogMonthlyandSeasonalTasksPowerOutageProtocol(withCistern)WaterFlowAlarmProtocol

1.

2.

3.

1.2.3.

DailyLogThesetasksshouldtakeverylittletimebutmustbedoneeverydayormorethanonceperday.

WeeklyTasksWeekly tasks constitute the majority of work on an aquaponic farm. Theseinclude plant production, fish sampling, water testing and cleaning. Tasks arebrokendownintofourphases,eachperformedonceperweekinasingledayorspreadoveradditionaldaysifrequired.Youcanchoosethedayoftheweekeachphasewilltakeplace,butwerecommendsettingaregularschedule.

Ifyouhaveaprimarymarketday(yourbiggestsellingday,oftenafarmersmarket),Phase1iscompletedthedaybefore.Marketdaysareusuallylong,thuslittlework isdone in thegreenhouseother thandaily tasks.AssumingonedayforPhase1andonedayformarket,Phases2–4aredoneoverthenextfivedays.Specific tasksmayvary ifyougrowdifferentplants.ExpectPhases1–3 tobeyourlongestworkdays.

NotesforPhase3Tocleantheheatpumpfilter:

Close the inlet and outlet valves and shut off the unit’s water circulationpump.Disassemblethefilterhousingandremovethefilter.Cleanthefilterwithahose.Reassemble theunit.Plug in thewaterpumpandopen the inlet andoutletvalves.

Tocleanthewaterpumpintake:

Shutoffthepump,thenclosethevalve(abovethepump).Unscrewthesuctionpipe(belowthepump).Inspectthepipeandpumpimpellerfordebris.Backflushingmaybeusefultodislodgedebris.

4.5.

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2.

3.4.5.

6.

Reassemblethesuctionpipeandopenthevalvebeforeturningonthepump.Confirmthepumpisfunctioning.

ScrubeitherTank1,2or3eachweek.Rotatesoeachtankiscleanedeverythreeweeks.Additionally,scrubthedrainscreensofalltankseveryweek,thenusethecleaningbrushtoremovethedrainscreenandpushanydebris intotheMWP.Reseatthedrainscreen.PoptheSPAoneachtanktoflushdebrisdowntheMWP.Useonlythededicatedbrushforeachtank.

TocleantheCFB:

Remove the seven outermost screens from the upstream side and the oneoutermostscreenfromthedownstreamside,leavingonlythetwoinnermostscreensthatcontaintheMBBRmedia.Use a hosewith good pressure to rinse each screen into theWasteTanks.Gentlytappingthescreenswillhelptodislodgeaccumulatedsolids.Replacethescreensbackintotheirrespectiveslots.RemovethetwoinnermostscreenscontainingtheMBBRmediaandclean.Replace the innermost screens,moving allMBBRmedia from outside thecontainingscreensbackintothecentralMBBRarea.Replacethelid.

Tocleantrays,hosethemoffthenagitateinabinofsoapywater(non-toxic,biodegradable,unscentedsoap).Rinsetrayswell,thenlayouttodry.Oncedry,stackinanoffsetpatterntoavoidhavingthemsticktogether.Storestackedtraysundertheworkbench.

WeeklySeedingChartWefinditisusefultohaveanerasablecharttonotewhatistobeseeded.Thisisparticularly helpful if the person doing the seeding is not the person decidingwhatistobeseeded.Tomakethecharterasable, laminateitandusedryerasepens.

CropLog

ACropLogkeepstrackofthemovementofasingleplantvarietyoverseveralcrops as they mature. Note only one plant variety per Crop Log. Include amarkerwithplantvarietyandseedplantdateoneachtrayandoneachraft.

FishSampleLogTheFishSampleLogisusedtorecordsamplingdataandcalculatetheaverageweightperfish.Sampleonetankeveryweeksothateachtankissampledeverythreeweeks.CopytherelevantinfofromtheFishSampleLogtotheappropriateCohortLog.

CohortLogTheCohortLog is used to track the number of fish, total biomass, daily feedrate, mortality and disease incidences, treatments and transfer dates for eachcohort. Each tank containing a cohort of fish must have an easily accessibleCohortLog.

Recordeverytypeofeventthatoccurs,suchasamortality,treatment,cohortsampling or tank transfer. Update the number of fish in the cohort andrecalculatethetankbiomassanddailyfeedrateeverytimeafishisremovedforanyreason.

MonthlyandSeasonalTasksThese tasks are less frequent but must be done regularly to ensure consistenthighproductivity.Werecommendputtingrepeatingdatesonyourcalendar.

ReplacingUVBulbsUV bulbs will typically need to be replaced every year (after 9,000 hours ofoperation).Afteroneyear, lightoutputwilldiminishbelow90%of thebulb’srating,decreasingitsgermicidaleffectiveness.

EachUVlampiscontainedwithinaclearquartzsleeve toprotect thebulbfromdirectcontactwithwater,allowingittooperateathightemperaturewithoutwarmingthepassingwater.Changingthebulbissimple,asitisnotnecessaryto

shutoffthewaterflowordraintheunit.Wheninstallingabulb,donotcontaminatethebulbsurfacewithdirtoroils

fromyourhandas contamination can reduce its lifespan. Inspectbulbprior toinstallation to confirm it is faultless, both in manufacture or due tocontamination.Carefullywipethelengthofeachbulbasyouinstallit.

IMPORTANT

Ifforanyreasonthemainpumpneedstobetemporarilyshutdown,alsoshutdownthepowertotheUVunits.Leavingthebulbspoweredwithnowaterflowwillrapidlyincreasethewatertemperatureintheunitswhichcandegradethelifeofthebulb.

T

MarketingandSales

HISBOOKISDESIGNEDasaguidetounderstanding,buildingandoperatingacommercialaquaponic system.Themarketingof fishandplants ismostly

identical to traditional aquaculture or vegetable farms with some aquaponicadvantages.Inthischapter,wewillbrieflytouchonthesubjectofsales.

AquaponicAdvantagesAsanaquaponicfarmer,youhaveseveraladvantagesinmarketing.

Year-roundProductionFormostcustomers (endconsumer, retailorwholesale) in temperateorcolderregions,purchasinglocallygrownfoodsallyear-round,particularlygreens,isafantasy.Aquaponicsmakesthisareality.

There is a hugemarketing advantage in producing quality local greens allyear.Inourlocale,foratleastfourmonthsoftheyear,wearequiteliterallytheonlylocalfarmwithanysortofleafygreens.Thisnotonlymeansourlettuceisinhighdemandandthatwecanchargeapremiumprice,italsohelpstoestablisha loyal customer base for the season when traditional farms offer similarproducts.

Increasingly restaurants and wholesalers are prioritizing locally sourcedproducts and promoting these to their customers. Offering such businesses ayear-roundsupplyisasubstantialadvantageovertraditional,seasonalfarms.

EthicalPlantsAquaponics provides year-round production using a tiny fraction of thewaterconsumed in traditional farmsandnoneof the chemical fertilizers requiredbymost hydroponic farms. You can use this to your advantage by educatingcustomers.Peoplewhocareaboutbuyinglocalwillusuallycareabouttheethicsofproduction.

EthicalFishWild fish populations are massively overfished, with many species at risk ofextinction.Usingoursystem,youwillraisehigh-qualitytroutinasystemwithnoimpactonwildpopulations.Raisedcorrectly,yourtroutwillbetender,pinkandthemostethicalchoiceforlocallymindedcustomers,whichwillcreatehighdemand.

AquaponicsIsSexyIt’s modern, it’s technologically advanced, it’s sexy. It’s a human-createdecosystem that produces the highest quality plants and fish with lowenvironmentalimpact.Thisisabigmarketingadvantage.

Display theuniquequalitiesofyour farmproudly. Include it inyour logo.Displayphotosofyourfarmatmarkets.Highlightitonyourwebsite.Anddon’tunderestimatehowbigadrawitisatafarmersmarkettohavebothgreensandfishdisplayed.

PotentialMarketsThere are four primary markets to consider: farmers markets, restaurants andretail stores,wholesale distributors and farmgate sales.Each have advantagesanddisadvantages.Thecommonbalancingfactorsarethepriceyoucanchargeversuseaseandvolumeofsale.

FarmersMarketsFarmersmarketsarethebreadandbutterofsmall-scalefarmers.Thereislikelynomarketwhereyouwillreceiveahigherpriceperunit.Farmersmarketsvarywidely depending on the location. Somemajor cities have numerousmarkets,

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oftenofvaryingquality,and itcanbedifficult toobtainaspot.Smaller townsmay have only one market. Most markets run seasonally (typically May toOctober in BC) but some are year-round. Year-roundmarkets will be a hugeadvantageforyouinnon-peakseasons.

Thedownsidetoafarmersmarketare:Requirementforspecificequipmentsuchastent,tableandsignage.Theconsiderableamountoftimeinvolved(lengthofmarketplussetup,teardownandtravel).Customerservicerequiresbeing“on”forlongperiodsoftime.Salesarenotguaranteedandwillvaryfromweektoweekdependingontheseason,weatherandcompetition.Marketfees(drop-inorseason).

Ourfarmersmarketboothwithsalespersonextraordinaire,Bre.

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Depending on the vitality of your local market(s), downsidesnotwithstanding,werecommendfarmersmarketsasyourfirstchoiceforsales.Thereyouwillaccesscustomersdirectlyandreceive100%oftherevenuefromyourproducts.Anylinksaddedtothesaleschainwillgreatlyreduceyourpriceperunit.Thesamecustomersmaypaythesameamountforyourproducefromasecondaryvendor,butthepercentagetoyouwillbemuchless.

Tipsforsellingatfarmersmarkets:

Ifyouarenotanextrovertedpersonwhocaneasilyengagewithstrangers,hire someone to run your booth. Having the right salesperson candramaticallyincreasethenumberofsales.Smileandengageeveryone.Manycustomersareshyandneedtobeinvitedinforacloserlookatyourbooth.Strive tohave thesamesalespersonat themarketeveryweekascustomerswillbuildabondwiththem.Be consistent with attendance. Attending the market regularly is key toestablishingregularcustomers.Strivetomissasfewmarketsaspossible.Beconsistentwithproducts.Varietyisgreatbutstrivetohavecoreproducts(headlettuce,saladmixandwatercressforus)availableeachmarketday.Presentationmatters.Havealargebannermadetohangonyourtent.Makeyourboothattractiveandinviting.Presentyourproductswell(rememberourmethodforkeepinglettucecrispandunwiltedinhotter/drierseasons).Remember the adage: “stack ’emhighandwatch ’em fly.”Whenbuildingyour display, create artificial height by placing crates or boxes underneaththedisplay.Abundance sells. As your products sell, keep your tables looking full bycondensingandcompactingthedisplay.Highlight aquaponics. In most markets, you will be the only aquaponicproducer.Makeabigdealofthistodrawpeopletoyourbooth.Highlightiton your banner. Display pictures of your system. Invite people for farmtours.Usetheuniquenatureofyourfarmtoyouradvantage.Thinkvalueadded.Livinglettucesellsformore.Smallbagsofherbs(e.g.,watercress)sellforapremium.Bringyourfermentedfishfertilizertosell.

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RestaurantsandRetailStoresNext to farmersmarkets, restaurantsand retail storesare likely thebestoptionforsales: thepriceperunit isusuallygood,anditemsaretypicallysoldbythecase.

Wedefinearetailstoreasanybusinessthatsellsdirectlytoendcustomers,adding one link between you and the customer. This contrastswithwholesaledistributorswho sell to retail stores and restaurants, adding two links betweenyou and the customer. In our experience, restaurants and retail stores are verysimilar markets. Both are likely to be individual business locations, and bothtendtopaysimilarprices.

Whenconsideringrestaurantsandretailstores,thekeyisdelivery.Youcanspendalotofextratimedeliveringtoindividuallocations.Wesuggestcreatingadeliveryscheduleofoneortwodaysaweektominimizedrivingtime.Considerdistancebeforeapproachingabusinessandapplyadeliverychargeifnecessary.Therearenumerousbusinessesanhourorsofromourfarmwhowouldliketobuyourproducts,butitmakesnosensetodeliverthatfarawaywhenwecanselleverythinglocally.

Typically restaurants and retail stores will have set prices for differentproductswhichmay vary seasonally and are often negotiable.Use your year-roundproductioncapacitytoyouradvantageinnegotiations.

Tipsforsellingtorestaurants:

Consistent supply ismandatory.Most restaurants have a stable year-roundmenu, and it is a big problem if their supply of a staple item like lettucemisses a week, forcing them to find an alternate source. You have theadvantage of offering year-round supply but planning will be required tomeetongoingcontracts.Offer consistent products, as you will likely supply a set menu. Theoccasional new productmay be useful for a special, but the bulk of yoursaleswillbethesameproductsagainandagain.It’s all about relationship. Sell yourself and your farm as much as yourproducts.Goodchefswanttobuildrelationshipswithgoodfarmers.

Tipforsellingtoretailstores:

• Varietyisbest. Incontrast torestaurantswhohavemorefixedneedsbasedonsetmenus,anever-changingselectionisbeneficialformanyretailstores.This is not, in our opinion, justification for you to grow a wide array ofproductsunlessretailstoresareyourprimarymarketandvarietyisrequired.

WholesaleDistributorsWholesalers serve as intermediaries between farmers and retail stores andrestaurants. They do not produce products and do not sell them to the endcustomers.Theyareanextralinkinthesupplychain.

Withveryfewexceptions,youwillmakelessperunit,oftenmuchless,bysellingtowholesalers.Thecounterpointtothisisthatmostwholesalerswilltakeasmuchsupplyasyoucanproduce,oftenby thepallet,andwillpickupfromyou.Itistheleastworkandbyfartheleastprofit.

Ifyouliveinareasonablysizedtownoranycity,youshouldbeabletofindmore profitablemarkets.We do not recommend selling to wholesalers unlessyouhaveexhaustedthepotentialtoselltomoreprofitablemarkets.Wholesalerscanbeusedasabackup tomove largequantitiesofunsoldproducts,butyourgoalshouldbetoavoidthem.

FarmGateSalesSellingdirectly fromyour farmseems likeanexcellent idea:youcanbeopenwheneveryouwant,andcustomerscometoyou.Butbeing“open”meansbeingavailable and ready to sell at any time or operating on the honor system, andcustomersmaybeunwillingtomakeaspecialtripjusttobuygreens.

Inourexperience, theonly times itmakeseconomicand timesense tosellfrom the farm arewhen people are already there. For us, this typicallymeansduringourmonthlytours.Almosteveryonewhoattendsourtoursbuyssomeofourproducts.Wedonotofferfarmgatesalesatothertimes.

MarketComparisonTheeasieritistosellyourproductsandthelargerquantityyoucanselltoonecustomer, the lower the price you should expect per unit. It is up to you todeterminewhatcombinationofmarketsfityouroutput,lifestyleandskills.

When setting prices, research the localmarket, includingwhat other local

producersarechargingatmarketsand thepricesat retail stores.Keep inmindthatmanycustomerswillpayapremiumforfreshlocallyproducedfood.

The following table details the prices we are paid or have been offeredduringmarketresearch.

TheRCASalesModelIn our local city of Duncan on Vancouver Island, there is a well-established,well-attendedyear-roundoutdoorfarmersmarket.Wesellthereeveryweekthatwe have sufficient supply (roughly 45weeks per year), and it constitutes ourprimary produce sales.We sellmost of the remainder of our produce to localrestaurants.

Wesellallofourfishwhole.Wesellthemajority,ifnotall,ofeachcohorttoonelocalrestaurant.Ourtroutisastapleitemontheirdinnermenu(seephotooncover).Whenwehaveexcess,we sell themdirectly to endcustomerswhopayalittlemoreperunitbutnotenoughtojustifytheextraworkforindividualsales.Wealwayshaveawaitlistforourfish.

Wehavealso sold toanorganicdelivery service (which fallsunder“retailstore”despitenothavingaphysicalstorefront).Thepriceperunitisgood,butthey are located an hour’s drive away (eachway), sowe havemostly phasedthemoutaswecanselleverythinglocally.

Weexploredtheoptionofwholesaledistributorsbutruled themoutduetothelowpriceperunit.Despitetheeaseofworkingwithwholesalers(theypickupandwilltakeeverything),forusthelowunitpriceisnottenable.

PromotingYourFarm

Depending on your local market, your capacity as a salesperson and yourobjectivesinfarming,youmayormaynotneedtoactivelypromoteyourfarm.Inourcase,wehavemoredemandthanwecansupply,andthuswedoverylittletopromoteourselvesasfarmersinordertodrivesales.Wedopromoteourselvesaseducators.

If you choose to promote your farm, you are likely to garner substantialinterestfromlocalmediaandgroupswhosefocusissustainability.ReachouttolocalnewspapersandTV—theywillbeinterested.

Keep an active social media presence. Posting updates on outlets such asFacebook,InstagramandTwitterwillkeepyourcustomersengagedandspreadnewsofyouroperation.

You will likely receive frequent requests for tours of your facility. Wesuggestholdingtoursatregularsettimesratherthanindividualbookings.Tourscanbepaidorfree.Weofferfreepublictoursoncepermonthandalsoregularlyhostschoolandcommunitygroups.

We recommend a gate and a large “we are closed” sign at the entrance toyourfarm,particularly ifyoucansee thegreenhousefromtheroad.Withoutagate and sign, uninvited curious guestswill oftenwander into the greenhouseunannounced,whichcanoccupyalotoftime.

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CreatingaBusinessPlan

E STRONGLY SUGGEST CREATING A BUSINESS PLAN as the first step inbecoming an aquaponic farmer. It is not possible for us to provide an

accurate business plan due to the large variables in building, operating andmarketing. This chapter will lay out the parameters necessary to create abusinessplanforyourfarm.

ConstructionCostsThecosttoconstructthesystemhasthegreatestvariability,thebiggestofwhichare acquiring property, labor costs, site preparation, choice of greenhousestructure/coveringandaccesstopower.

PropertyAcquisitionThis is the singlebiggestvariable. Ifyoualreadyownanappropriate site, thisfiguremay be zero. If you are planning on purchasing a site, this figure is asvariableasthepriceofland.Noteonlytheupfrontpurchasepriceisconsideredhere. Mortgage payments or rent are not included in this figure. They are inOperationalCosts.

LaborCostsOtherthanpropertyacquisition,thisislikelythebiggestvariable.Thedifferencebetweendoingmostof theconstructionyourselfandhiringcontractorswillbemeasured in tens and possibly hundreds of thousands of dollars. Building an

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aquaponicfacilityislaborintensive,andwhilemanyofthejobsarenotoverlycomplex,theyaretime-consumingandrequireahighlevelofskillandaccuracy.Asaruleofthumb,ifyouarehiringcontractorsforallconstructionjobs,expectthecostofthefacilitytoatleastdouble.

SitePreparationDependingontheproposedlocation,sitepreparationcanbeasquickas1–3daysor can be a major project costing tens of thousands of dollars. Choosing alocation with a suitable site that requires minimal excavation is stronglyrecommended.

GreenhouseApolycarbonategreenhousecostsasmuchasthreetimesthecostofadouble-layerpolygreenhouse(est.$75,000vs$25,000).Ausedgreenhousecanlikelybeacquiredforlessthan$10,000butmayhavesubstantialdownsidesandrisks.

PowerMany siteswill require a newor upgradedpower service to run an aquaponicfarm. Depending on the location, this could cost as little as a few thousanddollarstotensofthousandsifinamoreremotearea.

ListofInitialCostsThefollowingisalistofcoststhatshouldbedetermined,ascloselyaspossible,in your business plan. Some entries will require separation intomultiple sub-entries(e.g.,youmayrequiremultipleexcavations).Smallitemsthatarelikelytocostlessthan$100(e.g.,theheaterinthegerminationchamberanda50–60gal. barrel for the TankManifold) are not listed individually here but expectthemtocostseveralthousanddollarsintotal.

The following list is roughly organized from potentially highest to lowestcost: Property acquisition (down payment on property purchase) Contractor

costs:GeneralContractor(GC)CarpenterPlumber

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ElectricianHVAC(forheatpumpandwalk-incooler)GreenhouseinstallationteamGenerallaborAquaponic consultant, design and/or installation Greenhouse, 120′×36′(or40′)includingheater,circulationfans,roll-upsides,etc.

Siteprep:Excavation of site, Waste Tank area, sump, perimeter drain, cisternVarious fills (gravel, drain rock, sand) including delivery Hauling ofexcavatedmaterialSupportringsforfishtanksandTankManifoldWateraccess to greenhouse site Power installation (100 amp service togreenhousesite)Fiberglassfishtanks,3@8′diameter,1@4′diameterAir-to-waterheatpump

Electricalcomponents:panel,cables,outlets,boxes,solenoids,relays,etc.Plumbingandaerationcomponents:pipe,fittings,valves,etc.Woodproducts(mostly2×3s,2×4sandplywood)Walk-incoolerGreenhouseinstallation:

PieraugeringConcreteforpiers

HIDlamps/ballasts:12@1000W,7@400WUVsterilizersToolsrequiredforconstructionLDPE,20mil@14′wideRadialFlowSeparator,36″Polystyrene, 8′×2′ (min. 130 sheets; recommendedmin. 160 sheets) Lightmovers and rails (12) Building supplies (screws, bolts, staples, etc.) AirstonesAerationpumps(2)Waterpumps(2)ShadeclothCisternStainlesssteelcounter/sinkDissolvedOxygenmeterBuildingpermitfeesAquaculturelicensefeesIBCtotes(WasteTanks)Monitoringsystem

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HotwatersystempHcontrollerBackupoxygensystemEpoxyresinPaintNetpots,min.7,500SeedlingtraysTotesScales(2)TankscoversWashingmachineChestfreezerCFBmedia:screensandMBBRFishingnets(4)CleaningbrushesKnivesand/orscissorsSaladspinnerSmallitems(lessthan$100)Assumingnopropertyacquisitioncost,itmaybe possible, as a very rough estimate, to build our design with newcomponents (notably fish tanks) for as little as US$100,000 if you are aprofessional contractor with multiple skill-sets (e.g., carpentry, excavationandplumbing)andthecapacityandtimetodomostoftheconstructionworkyourself — in other words, with virtually no labor costs and with nounforeseensnags.Realistically, in most cases where you can assist with much of the

construction work and provide free or cheap general labor but will hirecontractors to lead each construction job,wewould expect our design to costbetweenUS$150,000andUS$250,000,notincludinglandacquisition.

Inextremecases,whetherdue toallcontractorworkand laborbeinghiredout at full price or unusual site problems, the design could cost more thanUS$250,000.

OngoingOperationalCosts

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Operationalcostsarealsohighlyvariable,notablylabor.Oursystemisdesignedtobefarmedby1–3peopleatlessthan40combinedworkhoursperweek(notincluding sales, marketing and administration). If all labor is done by theprinciple farmersas it is intended(nohired labor), thiswillgreatlychange theongoingoperationalcosts.

Unlessyouhaveamortgageorpay rent foryour site, likely thenextmostvariableexpenseispower.Forexample,thepriceperkWhourcanbemorethanfourtimesasexpensiveinBostonasinMontreal.

The following list is roughly organized from potentially highest to lowestmonthlycosts:Labor,hourly/weekly/monthlyMortgagepaymentsorrentOngoingmodifications,maintenance and repairs (higher in first fewyears)Watermanagementsupplies:pHcontrols

TestingkitsMineralsupplements

PowerInsurancePropane refill and tank rental Plantingmedia (e.g., coco coir, coco chips,rockwool)Cohortsoffish(250fingerlingseveryfourmonths)FishfeedSeedsFarmersmarketfeesToolsUVbulbreplacement(onceperyear)PesticidesandfungicidesPlasticbagsLicensingandmembershipfeesHIDlightreplacement(largeexpenseevery5–10years)Double-layerpolyreplacement(largeexpenseevery4–5years)OxygentanksrefillPromotion(businesscards,webhosting)Officesupplies(printerink,paper,receiptbooks,pens)T5bulb replacement (every1–2years)Bank fees andinterest

IncomeEstimatesMuch like construction and operation, it is similarly challenging to estimateincome.Thekeyvariablesare:(1)thetypeofplantsyougrow;(2)yoursuccess

atgrowingthoseplantsintermsofquality;(3)thenumberofharvestedplants,determined by the weeks to maturity and percentage of plants grownsuccessfully;and(4)thepriceyoureceiveperunit.

Foreaseofestimation,wecaneliminatethefirstvariablebyassumingyouwillonlygrowheadlettuce,soldaswholeunits.Thisisnotpracticalinreality,aswerecommendvarietyforbettersalesandapercentageofyourplantswillbeingloriousandthususedinsaladmixes.

Thesecondvariable(quality)isaddressedherebyonlyfactoringinunitsthatareofhighenoughqualitytobesoldaswholeunits.

Thethirdvariable(quantity)isaddressedbyshowingarangeofproductiontimes(from4–6weeks)andasubsetpercentageofsuccessfulproduction.Yieldsabove90%areunrealistic.

Thefourthvariable(price)isshownasanaverageperunit.Thelowestprice($0.50) assumes all heads are sold cheaply to awholesaler. The highest price($3.00)assumessellingaveryhighpercentagedirect toendcustomers for topdollar, such as at farmers markets, and selling the remainder to retail orrestaurants for a good price. If you live in a city with a strong local market,produceexceptionalqualityandareaskilledsalesperson,youraveragepriceperunitmayreach$2.50orhigher.

Inmost cases, we suggest conservatively estimating your average price atbetween $1.50 to $2.00, factoring in multiple types of market and seasonalvariability,andanaverageannualproductiontimeof5weekswith20%lossesorunsoldproducts.

Value-addedproducts, suchas livingbutterheadsor smokedfish, sell forapremiumandcangreatly increaseprofits.This chapterdoesnot factor in suchvalue-addedproducts, nor does it factor in secondary activities such as sellingfertilizer,raisingpigsoncropresidueorhavinganauxiliarygardenororchardfertilizedbyfisheffluent,allofwhichcanincreaserevenue.

Remember as well that your first year of production is gradual and takestwelvemonths or so to reach full capacity, assuming nomajor problems.Thetable below is based on full production capacity (starting year two). This isimportantforacashflowprojection.

Lastly, you should assume that at best youwill break even on raising andselling fish.Typically, fish turn a profit onlyon amuch larger scale thanyou

willbeproducing.For this reason, fish income isnot included in this chapter.Optionally,youcanremoveongoingfishexpenses(cohortsandfishfeed)fromthebusinessplanandestimatethatexpensesandincomewillbeapproximatelyequal.Donotremovefishincomeandexpensesfromacashflowprojection,asincomeisconsiderablydelayedfromexpenses.

IncomeEstimateTableThe following tablesarea roughguideonly to show thevariabilityof incomebasedonproductiontimes,productionsuccessandskillatmarketing.Thetablesshow estimates for 4-, 5-and 6-week production times, and at variouspercentagesofcropsold(from60–90%).

Asanexample,thehighlightedcellinthesecondtableshowsagrossincomeestimate based on a 5-week production time (in the troughs)with 80%of theharvestablesitesproducingmature,qualityplants(20%lossesorunsold)thatarethensuccessfullysoldforanaverageof$2.00perunit.Theformulaforthiscellis:6,192(harvestablesites)/5(weeks)×0.80(80%)=990plantssold990(plants)×$2.00(perunit)=$1,980grossweeklyincome4WeekProductionTime

5WeekProductionTime

6WeekProductionTime

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FinalThoughts

ODERN AQUAPONICS is still in its infancy. Like all pioneering ventures,gettinginonthegroundfloorhasuniquepotentialforgreatrewardsbut

also comes with great risks. Becoming a commercial aquaponic farmer willmeanthatyou,likeus,arenotjustfollowingbutactivelyexpandingthebreadthofknowledgeandhelpingtomovefarmingforward.Weurgeyoutotaketimetoweightherisksandrewardscarefullybeforebreakingground.

For those who opt to join us, we welcome you with open arms and lookforwardtocollaboratingwithyou.Weareavailabletoserveasconsultants,andweoffercustomdesignsofallsizesforbothDWCandtowersystems.Wecanbefoundatourwebsite:www.raincoastaquaponics.com.

Thisisanexcitingtimetobeapioneerinfarming.Goodgrowingandgoodhealthtoyou!

AdrianSouthern&WhelmKing

Resources

RaincoastAquaponics—ourwebsiteraincoastquaponics.comNewSocietyPublishers—ourpublisher,sourceofnumerousexcellentbooks

www.newsociety.comBrightAgrotech—makersoftheonlydriptowerswerecommend

brightagrotech.comPentairAquaticEcoSystems—primarysourceforaquacultureequipment

pentairaes.comWestCoastSeeds—supplierofallofourseedswestcoastseeds.comJeffersonSolenoidValvesjeffersonvalves.comMichaelTimmons3-dayAquaculturecoursefish.bee.cornell.eduCayugaAquaVentures—bestsourcetopurchaseRecirculatingAquacultureSystemsbyTimmons&Ebeling.c-a-v.net

SensaphoneWeb600—monitoringsystemsensaphone.com/products/sensaphone-web600-monitoring-system.php

Aqualarm.net—flowswitchaqualarm.net/cooling-water-flow-c-2BluelabpHcontrollergetbluelab.comDwyerInstruments—pressureswitchesdwyer-

inst.com/Product/Pressure/SinglePressure/SwitchesAmericanNettingandFabric—shadeclothamericannettings.comOMRIwww.omri.orgPesticidePropertiesDatabasesitem.herts.ac.uk/aeru/ppdb/en/PennStateGreenhouseIPM

extension.psu.edu/pests/ipm/agriculture/greenhouse/greenhouse-manual

Sources

Bradley,Kirsten.“Aquaponics:ABriefHistory.”milkwood.net/2014/01/20/aquaponics-a-brief-history

Brechner,Dr.Melissa,Dr.A.J.BothandCEAStaff.CornellControlledEnvironmentAgriculture:HydroponicLettuceHandbook.CornellUniversity,Ithaca,NY.cornellcea.com/attachments/Cornell%20CEA%20Lettuce%20Handbook%20.pdf

Davidson,JohnandStevenT.Summerfelt.“SolidsRemovalfromaColdwaterRecirculatingSystem:ComparisonofaSwirlSeparatorandaRadial-flowSsettler.”AquaculturalEngineering,Vol.33,no.1(June2005).sciencedirect.com/science/article/pii/S0144860904001049

Davidson,Johnetal.“EvaluationofDepurationProcedurestoMitigatetheOff-flavorCompoundsGeosminand2-methylisoborneolfromAtlanticSalmonSalmoSalarRaisedtoMarket-sizeinRecirculatingAquacultureSystems.”AquaculturalEngineering,Vol.61(July2014).sciencedirect.com/science/article/pii/S0144860914000545

“FeasibilityAssessmentofFreshwaterArcticCharandRainbowTroutGrow-outinNewBrunswick.”CommissionedbytheNewBrunswickDepartmentofAgricultureandAquaculture,April2010.www2.gnb.ca/content/dam/gnb/Departments/aaf-aap/pdf/Publications/Aqu/ArticCharrRainbowTrout.pdf

GreenhouseIPMManualwithanEmphasisonBiocontrols.PennStateExtension.PennsylvaniaIntegratedPestManagement.extension.psu.edu/pests/ipm/agriculture/greenhouse/greenhouse-manual

Holmgren,David.“12PrinciplesofPermaculture.”justlists.wordpress.com/2010/01/14/principles-of-permaculture

Klontz,GeorgeW.ManualforRainbowTroutProductionontheFamily-ownedFarm.UniversityofIdahoDepartmentofFishandWildlifeResources.1991.aqua.ucdavis.edu/DatabaseRoot/pdf/TROUTMAN.pdf

Morgan,Dr.Lynette.“NutrientTemperature,OxygenandPythiuminHydroponics”SimplyHydro,article4-3.simplyhydro.com/nutrient_temp.htm

Mousavi,SeyyedAlirezaetal.“EffectofCarbonSourceonAcclimatizationofNitrifyingBacteriatoAchieveHigh-ratePartialNitrificationofWastewaterwithHighAmmoniumConcentration.”AppliedWaterScience,Vol.7,no.1(Aug2014).DOI:10.1007/s13201-014-0229-z

Nick,SavidovPh.D:“EvaluationandDevelopmentofAquaponicsProductionandProductMarketCapabilitiesinAlberta.”IdsInitiativesFundProject#679056201.August17,2004.backyardaquaponics.com/Travis/Evaluation-and-Development-of-Aquaponics-Production-and-Product-Market-Capabilities-in-Alberta.pdf

Schmidt,Larryetal.“EnvironmentalAssessmentfortheUseofHydrogenPeroxideinAquacultureforTreatingExternalFungalandBacterialDiseasesofCulturedFishandFishEggs.”UpperMidwestEnvironmentalSciencesCenter,forUSGS,June2006.fda.gov/downloads/AnimalVeterinary/DevelopmentApprovalProcess/EnvironmentalAssessments/UCM072399.pdf

Shammas,NazihKh.“InteractionsofTemperature,pH,andBiomassontheNitrificationProcess.”Journal(WaterPollutionControlFederation),Vol.58,No.1(Jan.1986).jstor.org/stable/25042841

TheAquaponicsDoctors.theaquaponicsdoctors.com

Timmons,MichaelandJamesEbeling.RecirculatingAquacultureSystems,2nd

Edition,NRAC:CayugaAquaVentures,2002.

“UVInformation.”pentairaes.com/uv-information

“WhyMatrixMedia?”brightagrotech.com/products/matrix-media

Woynarovich,Andrásetal.“Small-scaleRainbowTroutFarming.”FAOFisheriesandAquacultureTechnicalPaper561.Rome:2011.fao.org/3/a-i2125e.pdf

Yue,StephaniePh.D.“AnHSUSReport:TheWelfareofFarmedFishatSlaughter.”HumaneSocietyoftheUnitedStates.humanesociety.org/assets/pdfs/farm/hsus-the-welfare-of-farmed-fish-at-slaughter.pdf

Zheng,Dr.Youbin,SiobhanDunetsandDianeCayanan.“GreenhouseandNurseryWaterTreatmentInformationSystem:UVLIGHT.”UniversityofGuelph,Ontario,Canada.

“ZipGrowTowerFAQ.”brightagrotech.com/hydroponic-farming/zipgrow-tower

Glossary

Airlock:abubbleofairtrappedinapipethatrestrictsorpreventswaterflow.Ammoniaoxidizingbacteria:bacteriathatoxidizeammoniaintonitrites.Array:asetgroupingoftowerrowsinatower-basedsystem.Autotrophic bacteria: derive their energy from inorganic compounds (e.g.,ammoniaandCO2).

Bacterial Surface Area (BSA): the amount of surface area available forcolonizationbybacteria.Bolt:rapidandtypicallyundesiredplantgrowthwhenvegetablessetseeds.Cohort:agrouporbatchoffishofsimilarage.Combination Filter Box (CFB): a unit designed specifically for the RCAsystemthatcontainstenfilterscreensandanMBBR.Crossbrace:ahorizontaltrussthatconnectsandstrengthensthetwohalvesofagreenhousearch.DeepWaterCulture(DWC):ahydroponicproductionmethodinwhichplantrootsaresuspendedinnutrient-ladenwater.Denitrification:absorptionofnitrogenbyplants.Dibbler:atoolusedtomakeaholeinsoil.Double-layerpolycovering:twolayersofflexiblepolyethylene,sealedaroundtheedgesandinflatedbyablower.Drain Down Effect: the release of retained water in the system in a poweroutageorpumpfailure.Effluent:watercontainingwaste.Endwall:averticalwallattheendofagreenhouse.Extruded polystyrene (“styrofoam”): synthetic polymer made from the

monomerstyreneconsistingofclosedcells.FeedConversionRatio:thecapacityofalivestockanimaltoconvertfeedintobodymass,measuredasaratiooffeedgiventoweightgained.Fingerling:asmall,youngfishwithscalesandworkingfins.Fry:thesmallest,youngestfishcapableoffeedingthemselves.Head:theamountofworkapumpmustdotoovercomegravity,verticalheightandfrictioninthepipe.Heterotrophicbacteria:derivetheirenergyfromorganiccompounds(e.g.,fishfecesandexcessfeed).HIDlamp:HighIntensityDischarge lamp, typicallyHighPressureSodiumorMetalHalide.Hydroponic Surface Area (HSA): the total surface area devoted to plantgrowth.Hygrometer:instrumentformeasuringhumidity.IBC tote (Intermediate Bulk Container): a plastic tank or tote with anintegratedpallet,designedtobemovedbyaforklift.Ingloriousplants:smaller,damagedordeformedplantsthatcannotbesoldaswholeunitsbutcanbeusedinsaladmixes.Kerf:thewidthofasawblade.Low Density Polyethylene (LDPE): thermoplastic made from the monomerethylene.Canbeflexibleorrigidatdifferentthicknesses.Manifold:apipeorchamberwithmultiplebranches.Meniscus:thecurveintheuppersurfaceofaliquidcausedbysurfacetension.MovingBedBio-Reactor (MBBR): a liquidspace filledwithbiological filtermaterialthatprovidesalargeBSA(BacterialSurfaceArea).MSDS (Material Safety Data Sheet): a document cataloguing informationaboutachemicalorproduct.MWP (MainWaste Pipe): the pipe into which the four fish tanks and RFSdraintoremoveeffluentfromthefacility.Nitrification:oxidationofammoniabybacteria.

Nitriteoxidizingbacteria:bacteriathatoxidizenitritesintonitrates.OMRI (Organic Material Review Institute): organic certifier of products,notablypesticidesandfungicides.PAR(PhotosyntheticallyActiveRadiation):thespectrumoflightavailabletoplants.Polycarbonatecovering:corrugatedpanelsofvaryinglayersandthicknesses.Pumpcurve:agraphshowingtheflowofapumpatvaryinghead.Purlin:ahorizontalstructuralmemberthatconnectsthearchesofagreenhousetoeachother.Pyrethrins:botanicalpesticidederivedfromthechrysanthemumplant.RadialFlowSeparator(RFS):apassiveconicalsettlingvesselwithnomovingpartsthatremoveslargesolidsfromliquid.Ridge vent: an adjustable passive vent running the length of the greenhouseroof.Roll-up sides: adjustable passive vents at the bottom of the greenhouse sidewallsthatareraised/loweredwithacrank.Shade cloth: woven polyethylene netting that blocks light transmittance by aspecifiedpercentage.Sourcewater:watersupplyusedtofillandtopupsystemwater.Supernatant:themostlyclearliquidatthetopofasettlingchamber.Systemwater:recirculatingwaterthatispumpedfromsumptotanksandwhichthenflowsbackthroughfiltrationandtroughstothesump.TankManifold:themixingvesselintowhichthefishtanksdrain.Tare: reset a scale to zero to compensate for the weight of the weighingcontainer.TheGoldenRatio:a ratioof the totalgramsofperfeedperdayandthe totalHSA (Gf/M2/Day) used to balance the system’s inputs and waste removalcapacity.Towers/tower system: a hydroponic productionmethod consisting of verticaltubes,typicallysquareorround,filledwithamediaintowhichplantrootsgrow.

AcronymsBSA

BacterialSurfaceAreaCFB

CombinationFilterBoxDWC

DeepWaterCultureHSA

HydroponicSurfaceAreaMBBR MovingBedBio-ReactorMWP

MainWastePipeRCA

RaincoastAquaponicsRFS

RadialFlowSeparatorSPA

StandpipeAssemblyUVT

UltravioletTransmittance

Index

Aacidity,water,51aeration,water.seealsoair

stonesblowerinstallation,107–109pipe,106water,52–54

AgriculturalExperimentStation,4airstones,52,53,108,109–110,213airtemperature.seealsohumiditydailylogs,233environmentalcontrols,220–221greenhousecooling,26–27greenhouseheating,25–26sourceheatpumps,28andwatertemperatures,28

air-to-waterheatexchanger,29

algaeineffluent,56humicacid,42hydrogenperoxide,175tankcleaning,172,178ultraviolet(UV)sterilization,41–43,180

alkalinity,water,51AmericanNettings&Fabric,Inc.,127

ammoniabacteriaoxidizing(nitrification),38,61–62,144,147biofilteractivityandwatercalciumlevels,17conversionbybacteria,2–3effluent,56–58initialsourceof,157levelsinwaterfromfishwaste,1nitrifyingbacteria,144asnitrogen,145plantsymptoms,211purging,180recordkeeping,237testing,134–135

aphids,215–216,222aquaculture,defined,1AquaponicGardening(Bernstein),16

aquaponicsdefined,1historyof,3–4plantsystems,5–6

azadirachtin,226

BBacillussubtilis,226

backupsaeration,water,53–54dissolvedoxygen(DO)meter,134monitoringsystem,131–133oxygen,55,128–131power,128–131poweroutageprotocol,243pumps,54waterflowalarmprotocol,244

backyardsystems,13bacteria.seealsobacterialsurfacearea(BSA)ammoniaconversion,2–3beneficial,41

hydrogenperoxidetreatment,175–176mineralizing,144nitrifying,144oxidizing(nitrification)ammonia,38,61–62,144,147roleof,143saltbathtreatment,177–179UVsterilizers,144–145

BacterialColdWaterDisease,175bacterialsurfacearea(BSA)biologicalfiltration,38–39DripTowerSystems,9–10DripTowerSystemsandDWCcompared,11–12wasteremovalcapacity,61–62

bears,219Bernstein,Sylvia,16biodigestion.seefermenting

biofiltersabout,38capacity,61–62defined,143establishing,156–160fishfeedingtechnique,171

biologicalfiltration.seebiofiltersbiomass(totalweightoffish)dailyfeed,170dissolvedoxygen,154feedconversionratio,163firstcohort,160–161GoldenRatio,62–66harvesting,180–181recordkeeping,164–165,231fortransport,166–167

biosecurityprotocols,173birds,218botanicalpesticides,41Botanicare,210BrightAgrotech,209brushes,cleaning,139BTi,226BTk,226bufferingpH,150–151businessplan,253–258butterheadlettuce,186

Ccabbageloopers,216

calciumdeficiency,210hydroxide,51,151–153recordkeeping,237sock,161,233systemcycling,160testingfor,134–135

CertificateofFishHealth,164chelatediron,146chemicalwatertesting,146–147chestfreezer,140chinampas,3chloramine,41chlorine,41circulationfans,74cisterns,60,119–121,243

cleaningbrushes,139easeof,filtrationsystem,37filters,21,67harvest,207heatexchanger,117netpots,137,208pumps,116rafts,92,208screens,37tanks,172,230

closedloopaquaponicsystem,3–4cold-watervswarm-wateraquaponics,62–63combinationfilterbox(CFB).seealsomovingbedbio-reactor(MBBR)calciumhydroxide,51constructing,100–102dailylogs,233filters,39housingforMBBR,40–41installationlayout,94–95installing,104plumbingconnection,105–106waterflow,32

commercialsystems,13constructioncosts,253–256

constructionrecommendations,70

cooler,walk-in,122–123

coolingair,greenhouse,26–27GerminationChamber,123–125germinationchambers,45–47water,27–28

costsconstruction,253–256currency,18DeepWaterCultureSystems(DWC),8–9filtrationsystem,37greenhouse,newvsused,23–24initial,254–256labor,253ongoing,256–257

cotyledon,46–47countertop,stainlesssteel,140–141covering,greenhouse,73–74croplog,239croprotation,235culturalcontrols,220currency,costs,18cycling,system,155–162

Ddailyfeedamount,170DailyLightIntegral(DLI),44dailylogs,229–230DeepWaterCultureSystems(DWC)about,5–6advantages,8–9aeration,52design,31draindowneffect,59DripTowerSystemscompared,10–11pesticideinfiltration,223–224sump,32

denitrification,61–62diatomaceousearth,216,217,226

dibblerplate,136–137directseeding,188–189diseases,plants,213–215dissolvedoxygen(DO),134,153–154,237dogs,farm,218double-layerpolyinflationblower,27draindowneffect,59,89,119drainplumbing,90drain-to-wastesystem,2

DripTowerSystempumps,56sump,32

DripTowerSystems,5–6,9–10DWCcompared,10–11

Eearwigs,216–217ecomimicry,4–5ecosystem,natural,4–5effluent,56–58electrical,greenhouse,75–77electricallydrivenswampcoolers,26endwalls,greenhouse,73

energyassessments,28consumption,filtrationsystem,37

environmentalcontrols,220–221epoxyapplications,80DissolvedOxygen(DO)meter,134maybetoolbrazen???sexinessofaquaponics,246

ethicalfish,246ethicalplants,245–246extrudedpolystyrenerafts,34–35

Ffans,greenhouse,25farmdogs,218farmersmarkets,201,205–206,246–248farmgatesales,249–250

feedcarnivorousspecies,169–170conversionratio,163dailyfeedamount,61,170dailylogs,233nutrients,145–146storage,141

fermentingwaste,57

fertilizerschemical,2fermentingwaste,57nutrientrecycling,148–149

filtrationbiologicalfiltration,38–39CombinationFilterBox(CFB),40–41,100–102,104DripTowerSystemsandDWCcompared,12effluent,57mechanicalfiltration,37–38RadialFlowSeparator(RFS),39–40screeninstallation,103–104swirlfilters,38systems,37–39

fish.seealsobiomass(totalweightoffish);feedethical,246feedingtechnique,171firstcohort,160–161harvesting,180,181–183health,173–175nets,139pathogens,17,174–175purging,179–181quarantine,168–169recordkeeping,231,233,240,241sampling,170,237,240,241sourcing,164species,163tempering,168transport,165–167waste,1

fishfarms,opennetpens,1fishtanks.seealsotank

manifoldbasicrequirements,35–36cleaning,172covers,139installationlayout,94–95installing,95–97insulation,28rotation,171–172sandinstallation,97sterilization,172UVsterilizerplumbing,112–113waterflow,32

Flavobacterium,174foggers,227foundation,greenhouse,70–71frame,greenhouse,72freezer,chest,140frictionloss,55frogincident,17,55

fungalinfectionshydrogenperoxidetreatment,175–176powderymildew(PM),214–215

fungicides,219fungusgnats,215

Ggasboilers,28generalcontractors,69generators,129“geomembrane.”seeLowDensityPolyethylene(LDPE)

germinationrecordkeeping,236seeds,191substrates,136germinationchambersconstruction,123–125plantingseeds,189–191seeds,188spacerequirements,45–47

glassgreenhouses,24GoldenRatio,61–67gramsoffeeddaily,61

greenhouseairheating,25–26construction,70–75cooling,air,26–27costs,254covering,24–25,73–74electrical,75–77fans,25heating,25layout,29–32newvsused,23–24roll-upsides,74size,22–23venting,25windconsiderations,20

greenleaflettuce,186“groundinfiltration,”21groundsourceheatpumps,28

Hhardness,water,134–135

harvestingplants,201–204plants,cleanup,207–209recordkeeping,234workbench,60

harvestingfish,180,181–183“head,”defined,54headlettuce,16

heatinggerminationchambers,45–47greenhouse,25–26heaterinstallation,74–75pumps,29,116–119seedlingarea,47–48ventilationcycle,221water,27–28,49–50

HID(HighIntensityDischarge)lighting,45,121–122highpressuresodiumlights,75high-pressurewatermisters,26humicacid,42

humidityenvironmentalcontrols,220–221germinationchambers,45–47lid,191

HVACprofessionals,29,116,122–123hydrogenperoxidetreatment,175–176HydroponicLettuceHandbook,45hydroponics,1,2HydroponicSurfaceArea(HSA),61–67hydroxides,pH,150–151hygrometers,221

Iimperialmeasurements,17–18incomeestimates,257–259inletplumbing,90insecticidalsoap,226IntegratedPestManagement(IPM)protocols,219internet,greenhouse,77iron,134–135,146,237irondeficiency,211

Kkale,186,204knives,139

Llaborcosts,253ladybugs,222landcharacteristics,19landrights,21–22lethalconcentrationcalculation,pesticide,222–225lettuce,186,202

lightingDeepWaterCultureSystems(DWC),8–9DripTowerSystemsandDWCcompared,11environmentalcontrols,220–221germinationchambers,45–47,123–125HIDlights,seedlingtable,121–122highpressuresodiumlights,75lightmovers,45seedlingarea,47–48sunlight,44–45supplemental,43–45UVbulbs,232

LightRaillightmovers,45liquidcomposting.seefermentingLittleGiantpumps,116LowDensityPolyethylene(LDPE)seedlingtable,121–122sump,58–60sumpconstruction,78troughliner,34,85–89

MMainWastePipe(MWP),21,95mammals,218marketcomparison,250marketingadvantages,245–246marketingandsales,245–251martens,218Matalafilters,104McLarney,William,3McMurtry,Mark,3measurements,metricandimperial,17–18mechanicalfiltration,37–38MediaBedSystems,5–7

metricmeasurements,17–18mineralization,water,51mineralizingbacteria,144minerals,146mink,218monitoringsystem,131–133monthlytasks,232,242MovingBedBio-Reactor(MBBR),38,39,40,52,103MSDS,225mustards,186,204

NNatria,215netpots,136,137,194,197,202–203,209NewAlchemyInstitute,3nitrates,61–62,134–135,145nitrification,38,61–62,144,147nitrites,134–135,145,237nitrogendeficiency,210NutrientFilmTechniqueSystems(NFT),5–6nutrient,plants,209–211nutrientrecycling,148–149

OOMRIlistedpesticides,214,222,225

operationsbusinessplan,253–258firstyear,161–162fullcapacity,162incomeestimates,257–259marketingandsales,245–251ongoingcosts,256–257plantsproductioncycle,209recordkeeping,164–165

oxidizeammonia(nitrification),38,61–62,144,147

oxygenbackup,55,128–131dissolvedoxygen(DO),134,153–154

oxygenavailabilityDripTowerSystems,9–10

DripTowerSystemsandDWCcompared,12

oystershells,crushed,217

Ppackaging,harvest,137,234

paintingcombinationfilterbox(CFB),102feedstorage,141germinationchamber,124layoutmarking,94pumpcovers,116rafts,35,92–93sump,77,79troughs,81,89

passivecoolingsystems,26–27pathogens,41–43,174–175,177–179peakvent,27pelletedseeds,187–188Pentair,35permaculture,aquaponicsand,5personalprotectiveequipment(PPE),226–227

pestcontroldailylogs,233DeepWaterCultureSystems(DWC),8–9pesticides,222–227predatoryinsects,222stickytraps,221

pesticidesbotanical,41foggers,227

IntegratedPestManagement(IPM)protocols,219lethalconcentrationcalculation,222–227OMRIlisted,214,222,225personalprotectiveequipment(PPE),226–227pyrethrins,41,222,226re-entryinterval,226table,226

pests,plants,215–217

pHmonitoringabout,50–51calciumhydroxide,151–153controller,133–134dailylogs,233management,151–153potassiumdeficiency,210potassiumhydroxide,151–153preferences,149–150recordkeeping,237

phosphoricacid,51phosphorous,134–135

PhotosyntheticallyActiveRadiation(PAR),43pH(potentialofhydrogen),50–51pillbugs,217plants.seealsoseeding;

seedlingcroplog,239dailylogs,233diseases,213–215ethical,245–246growingmedia,191harvesting,201–204inspection,199,220maturing,198nutrients,145–146observation,148packaging,203,207pests,215–217recordkeeping,235

rootzoneandwateraeration,52seeds,187–188selection,185stickytraps,221storage,201–204substrates,136thinningandspacing,8–9,196–197,235transplantingtotroughs,193–194transplantschedule,196washing,205wateringingreenhouse,199–201

plantsystemsDripTowerSystems,9–10DripTowerSystemsandDWCcompared,11

plumbing.seealsospecific

plumbingsystemslayout,94–95pumpsideinstallation,110–116troughinstallation,89–91troughsideinstallation,105–106

polycarbonatecovering,24–25polyethylene(“poly”)coverings,24,127poroussilica,52

potassiumdeficiency,210hydroxide,51,151–153recordkeeping,237testing,134–135

potentialofhydrogen(pH).seepHmonitoringpots,net,136,137,194,197,202–203,209powderymildew(PM),214–215

powerbackup,128–131consumption,60outages,17outagesprotocol,243andwateraccess,19–20,254

PRAqua,35predatoryinsects,222productioncycle,209production,year-round,245promotions,251propane,heatingair,26propanelines,74–75

propertyacquisition,253considerations,18landcharacteristics,19landrights,21–22livingonsite,22powerandwateraccess,19–20sitepreparation,70,254wastedisposal,21wind,20

pumps.seealsospecific

pumpscentrifugal,54–55heat,installation,116–119selection,115–116TowerSystemPumps,56

purgetank,168,179–181purging,179–181PVCglue,93PVCpipe,94Pyganic™,223pyrethrins,41,222,226pythiuminfection,213–214

Qquarantine,fish,168–169

Rradialflowseparators(RFS),21,32,38,39–40,99installationlayout,94–95TankManifoldconnection,100

raftscleaning,92,207–208construction,91–93directseeding,188–189placement,195plants,thinningandspacing,196–197styrofoam,34–35,91–93transplantingseedlings,193–194

rainbowtrout,16RaincoastAquaponicsGreenhouse(RCA)design,32DWCdesign,30filtrationsystems,39heatpump,29plants,185–186salesmodel,250–251standardoperatingprocedures(SOPs),229–244system,31troughs,33–34

rainwater,cistern,60Rakocy,James,4rats,218RecirculatingAquaculture(Timmons&Ebeling),67recordkeeping,164–165,173,229–230,233refrigerationsystems,28regenerativeblowers.seeaeration,waterrestaurants,248–249retailstores,248–249“returnofsurplus,”5roll-upsides,greenhouse,26,74romainelettuce,186rootheating,seedlingarea,47–48rootzone,52

S

safety,77–80,225saladdryer,138saladmixes,205–206,234salesandmarketing,245–251saltbathtreatment,177–179Sanders,Doug,3sandinstallation,97scales,138scissors,139screenfilters,38seasonaltasks,232,242

seedingchart,231direct,187–189planting,189–191recordkeeping,236,238schedule,196trays,236workbench,60

seedlingarea,47–48dailylogs,233dibblerplate,136–137moving,191–193recordkeeping,236schedule,196substrates,136transplantingtotroughs,193–194traysanddomes,135–136

seedlingtableconstruction,121–122HIDlights,121–122LDPEliner,121–122recordkeeping,236seedgrowthcycle,188watering,48

Sensaphone,131sexinessofaquaponics,246shadecloth,127–128greenhouse,26

“shut-offhead,”pump,54side-to-sideplumbing(u-turn),90–91sink,stainlesssteel,140–141sink,washdown,141sitepreparation,70,254slugs,217sodiumchloride.seesaltsoillessproductionsystem,1–2solarpanels,28solidsremovalcapacity,37standardoperatingprocedures(SOPs),229–244standpipeassembly(SPA),36,39,95,97–99,233sterilization.seeultraviolet(UV)sterilizationstickytraps,221styrofoam,34–35,91–93substrates,136

sumpairstones,52construction,77–80dailylogs,233draindowneffect,59functionsof,58–60greenhouselayout,29–32

sunexposure,18–19sustainability,aquaponicsand,5Sweetwaterairstones,52swirlfilters,38systemhead,110,113–115

Ttankmanifold,32,36,94–95,100tasks,monthly,232,242tasks,seasonal,232,242tasks,weekly,230–231temperature,air.seeairtemperaturetemperature,water.seewatertemperaturetemperingfish,168thermalmass,8–9,27thinningandspacing,plants,8–9,235Todd,JohnandNancy,3tools,small,138–140totes,137traysanddomes,seedling,135–136

troughsaerating,53construction,81–85construction,partslist,91dailylogs,233designprinciples,32–33linerinstallation,85–89placementof,84–85plumbinginstallation,89–91recordkeeping,235seedgrowthcycle,188

two-pumpdesign,17

UUltravioletTransmittance(UVT),42ultraviolet(UV)bulbs,232ultraviolet(UV)sterilizationalgae,41–43,180bacteria,41–43,144–145biofilterestablishment,156–160fish,firstcohort,160–161fishtankplumbing,112–113greenhouselayout,29installation,110–112pathogens,41–43purging,180

UnitedNationsFoodandAgricultureOrganization,219

V

ventilationcirculationfans,74environmentalcontrols,220–221greenhouse,25,26,27heatingcycle,221

Wwalk-incooler,122–123warm-watervscold-wateraquaponics,62–63

washdownsink,141washingmachine,139–140

wastedisposalMainWastePipe,21propertysite,21WasteTanks,21

wastemanagementeffluent,56–58goldenratioremoval,61–62recordkeeping,237tanks,21,36wastewater(effluent),21

wasteremovalcapacityBacterialSurfaceArea(BSA),61–62HydroponicSurfaceArea(HSA),61–62nitrates(denitrification),61–62oxidizeammonia(nitrification),61–62

water.seealsoaeration,water;airstones;ammonia;pHmonitoring;water

temperatureacidity,51chemicaltesting,146–147cistern,60consumption,49DissolvedOxygen(DO),153–154externalsource,169flowalarmprotocol,244flow,filtrationsystem,37heatingandcooling,27–28hot,140labanalysis,179plantsingreenhouse,199–201qualitymanagement,51–52,149sampling,147–148seedlingarea,47–48source,155sourceinstallation,93tankexcavation,80–81testing,20,134–135,237

watercress,186,202

watertemperatureandairtemperatures,28cold-watersystems,49–50,153criticalfactor,27dailylogs,233environmentalcontrols,220–221regulationsystems,28

weeklytasks,230–231wholesaledistributors,249windconsiderations,20workbench,60,122workflow,DripTowerSystems,9–10

YTheYear-RoundSolarGreenhouse(SchillerandPlinke),29

ZZipGrow™Towers,8,31,52zoning,18

A

AbouttheAuthors

DRIAN SOUTHERN is an aquaponic farmer and entrepreneur from theCowichanValleyonVancouverIsland,BC.Afterfoundingandoperating

an intensive urban farm andmanaging a local farmersmarket, he is currentlysteeped in all things aquaponics.After years of systemperfection, he foundedRaincoastAquaponicsandraisestroutandvegetablesforaliving.

WHELMKING isabusinessmanager,projectmanagerandentrepreneur.Hehasworkedandconsultedinawidevarietyoffieldsincludingthearts,agriculture,publishing,mediaandlaw.Hepursueshispassionsoffoodsustainability,ethicsandrockclimbinginNanaimo,BC.

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IssuesandResources

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RecycleOldElectronicsResponsibly

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