Copper Sulfate & Alkalinity - University of KentuckyHigh alkalinity water Low alkalinity water 11 -...
Transcript of Copper Sulfate & Alkalinity - University of KentuckyHigh alkalinity water Low alkalinity water 11 -...
Algae, Copper Sulfate & Alkalinity
Herbicides for Algae
• Copper sulfate – inexpensive (chelated copper?)
• Endothal (Hydrothol) – some toxicity to fish
• Sodium Carbonate Peroxyhydrate(Green Clean, et.al.)
Copper
Photosynthesis Inhibitor
pH
• pH indicates whether water is acid, neutral or base
• A range of 6.5 to 9.0 is desired for aquatic life
Fig. 2. pH scale showing recommended range (Wurts & Durborow, 1992).
A pH of 7 is neutral, pH < 7 is acidic , pH > 7 is basic (alkaline).
0
4.0
7
9.0 11
14
6.5
pH
Death DeathDesired range for
aquaculture
Alkalinity
• Measures how much base is present in water
• Must be above 20 ppm to use copper sulfate
• Can be increased with liming
Alkalinity & pH
• Low pH is common with low alkalinity
• Increasing alkalinity increases pH
• Alkalinity stabilizes pH
Changes in pH during a 24-hour period in waters of high and
low total alkalinities (Wurts and Durborow, 1992).
pH
High alkalinity water
Low alkalinity water
11 -
10 -
9 -
8 -
7 -
6 -
5 -
Early
Morning
Early
Morning
Late
Afternoon
Usual Recommendation
• For algae in a “farm pond”
• 1.0 ppm Copper Sulfate
• 2.75 lb/acre-foot
• What about fish?
Copper Toxicity
• Copper is toxic to fish
• Low pH increases toxicity
• Low alkalinity prolongs toxicity
Liming
• Adding ag. limestone will increase pH & alkalinity
• Collect soil samples from pond bottom, to a depth of 6 inches
• Send samples to soil testing lab
• Use recommendation for “Alfalfa”
Ponds with Water
• Collect water sample
• Test for total alkalinity
• If total alkalinity is < 20 mg/L, pond should be limed
• Some swimming pool test kits measure alkalinity
Benefits of Liming
• Helps prevent wide swings in pH
• Enhances effect of fertilization
• Adds Ca & Mg to water
• Improves safety for using copper
Copper & Alkalinity
• Cu2SO4 in water = 2Cu+2 + SO4-4
• CaCO3 in water = Ca+2 + CO3-2
• MgCO3 in water = Mg+2 + CO3-2
Copper & Alkalinity
• High alkalinity reduces effectiveness of copper
• Low alkalinity prolongs copper toxicity
• Copper treatments must be adjusted for alkalinity
Warning: Avoid Using
• Hydrated & Quick (Slaked & Burnt) Lime
• These compounds can cause sudden, large increases in pH
• Rapid pH changes can kill fish
Applying Copper
• Pillow case – “the classic”
• Trash can and siphon hose
• Criss-cross the entire pond
Spot Treatments
• Large floating mats of algae & low alkalinity
• Supersaturated solution
• Hand sprayer
Full Pond Treatments
• Use total dose for the whole pond
• Algae have no roots, leaves, stems
• Do not treat if algal coverage is more than 25-30 % -- may cause oxygen depletion
• Do not reduce dose by 2/3 or 3/4
Aquatic Food Chain
• Phytoplankton
• Zooplankton
• Small Insects
• Small Fish (minnows & bluegills)
• Large Fish (bass & catfish)
Aquatic Weeds
Filamentous AlgaeMoss, Pond Scum
Bluegreen Algae
Chara(an alga)
Duckweed
Watermeal
Southern Naiad
Water Primrose
Variable Leaf Pondweed
Spatterdock(Water lily)
Cattail
Willow
Look Alikes
1
2
3
Look Alike ID
1. Coontail
2. Slender or Spiney-Leaf Naiad
3. Chara
Pond Call Questions
• How big – acres?
• How deep?
• Extensive shallow areas?
• Livestock grazing/watering?
• Cropland/fertilizers/turf strip?
Slide Shows On-line www.ca.uky.edu/wkrec/WurtsPrespage.htm
On-line Literaturewww.ca.uky.edu/wkrec/WurtsLitpage.htm
ExtensionAquacultureSpecialist
Dr. Bill WurtsKentucky StateUniversity CEP