I have a place on a lake that was built back in 1937. When I was a kid back in the seventies I remember that they had a weed or algae problem. They had a float constructed that they put bags of copper sulfate on and let the wave action dissolve it into the lake. I have no idea how much that they put in the 25.4 acre lake then. My question is this could all the copper sulfate that they put in keep the benificial weeds from growing in the lake? What are your thoughts? An aeration system is now in place.