our 8 yr old swimming pond had leeches for the first time this year. It's a large pond, about 35,000 gallons and 7 feet deep. stone and sand bottom with water fall for aeration. We have managed to keep water clear in the past with Pond Boss Beneficial Bacteria and the occasional dose of Think Purity Algaside. However to kill the leeches we gave a few heavy doses of copper sulphate and then also some chlorine. The family wouldn't swim in the pond with leeches and didn't want fish. The chlorine and copper killed all the snails and leeches. I am now having trouble getting the water clear again...probably the copper at the bottom of the pond is killing the beneficial bacteria that I add. I hate to keep adding the bacteria if its just dying off, as its expensive. will time resolve this or is there something I can do to get my nice clear water back? I know it did take a few years to get a real clear pond...do I need to reestablish the Eco system all over again?