I have an 8,000 to 10,000 square foot pond with an average depth of 3-4 feet. It supports three species of trout. The water normally darkens from suspended algae each year when it warms. In addition to that, this year we have brown suspended algae in the water for the first time. What and how much do you recommend to resolve the algae problem without hurting the trout.
DM, Fairlee, VT
Cutrine-Plus Liquid is a fast-acting algaecide that will control most varieties of algae it makes good contact with. Cutrine-Plus Liquid can be applied to your pond without harming your trout, provided the calcium carbonate hardness of your pond is 50 ppm or more. A 10,000 sq. ft. pond with an average 4’ depth is 1 acre-foot and would require 86 oz. of Cutrine-Plus Liquid. Mix 13 oz. of Cutrine-Plus Liquid with enough water to make 1 gallon of solution and spray over the pond surface. 7 gallons of solution will treat your entire pond one time. Repeat treatment may be needed to make good contact with all the algae.
Water can be tested for calcium carbonate hardness by taking a sample to your local water company or with Water Hardness Test Strips.
GreenClean Granular is a second fast-acting algaecide that will control some varieties of algae but not all types. GreenClean will not harm fish, including trout. Your 10,000 sq. ft. pond would require 10 lbs. of GreenClean per treatment. Again, repeat treatment may be needed if algae begins to return.
AquaClear Pellets are an excellent natural, beneficial bacteria that will strip nutrients from the pond. Most algae will thrive in a nutrient filled pond. Ponds filled with fish and years of decayed vegetation normally have a high nutrient level. By reducing the nutrient level the amount of new algae should be significantly reduced. AquaClear Pellets will not harm trout. A 10,000 sq. ft. pond would require 5 lbs. of AquaClear Pellets weekly for a minimum of 4 weeks or until desired water quality is achieved.
Please feel free to e-mail me or post questions you may have and I will respond accordingly.