I take care of a 1500 gal FOWLR tank. Outbreak of Amyloodinium (Marine Velvet) wiped out all fish! Was advised to use Coppersafe, brought in more fish, they too died. Now I'm advised that once copper solution is in the tank, I must continue to use it forever--if level gets too low, mutated parasite will reappear. Parasites remain in rocks, sand, etc. Is this true? I'll be buying Coppersafe for years, if so. Help!