yes, although i cannot remember the name of it. may father used to have a large garden pond in the front of his house, about 4 1/2 feet deep and 12 feet circular. it was full of large goldfish. he would dump in this blue liquid that turned the water a beautiful ocean blue, was safe for the fish, and killed all of the algee. I will try to get ahold of him tomorrow and ask him what that was called.