Blue Planet Pond Sludge Buster breaks down and reduces pond sludge and algae for a cleaner and clearer pond. Pond sludge occurs as a result of fish waste as well as food, leaves and algae settling to the bottom of the pond. The decomposition of these materials produces toxic gas and reduces oxygen in the water making it an unhealthy environment for your fish. Containing natural beneficial bacteria, Pond Sludge Buster counteracts the nutrients needed by algae reducing its growth and breaking down the sludge.