Pond Boss Forums GENERAL QUESTIONS Water chemistry copper concentration

I am trying to manage a pond used for swimming and fishing. I have taken over from someone who put too much copper sulfate in the pond. It is a 1.7 acre pond and I recently stocked it with fish after being told that copper sulfate is only harmful to fish when lots of algae gets killed at one time. Now many fish are dying and I think it's because of the toxicity of the high amount of copper that was used (120 lbs. over a 5 week period). If I test for copper in the water, what would be a safe amount to have present to be able to re-stock the pond? Or, how long would you guess I would have to wait till it would be safe for fish? I guess I will need to test for total alkalinity to get a picture of how toxic the copper is in our water. Thanks, Jeff

If you are not testing with atomic absorption method then you want no measurable copper in the water. Even low doses of chronic copper will produce internal stress to fish but not kill them right away. different species of fish have different killing doses from CuSO4. If the copper is killing fish what do you think it did to all the other micro-organisms lower on the food chain in the pond??. Free Copper ions should fairly quickly form copper carbonate and percipitate to the bottom. However this will depend on the hardness of the water.

Thanks. I'm certainly aware that there are probably little if any lower forms of life still alive in that pond. Even before the fish started dying, we had decided not to use copper sulfate anymore. How can I get the food chain in the pond back where it should be? Should I stock daphnia? Or will it take a lot more than that? What else would you suggest?

From what I have read, chelated copper sulfate is the thing to use. Cutrine Plus is what I have been using since I found out that straight copper sulfate was not a good thing.

First thing to be done is wait till all copper out of the water column. No use stocking organisms if they are going to be killed by copper toxicity. Nature is prety good at re- colonizing damaged habitats providing the toxicity level has subsided. Often reseeding invertebrates speeds the recovery & recolonization processs.