Aquascape® 98890 1 pt Sludge & Filter Cleaner. Aquascape Sludge & Filter Cleaner effectively reduces fish waste and decaying organic plant material in ponds. Each bottle of Aquascape Sludge & Filter Cleaner is packed full of five pure strains of heterotrophic bacteria, helping to maintain a strong biological balance in your pond while quickly cleaning rocks, gravel, and filter pads. Our Sludge & Filter Cleaner’s potency ensures consistently effective treatment, and the included marigold and humic acid help to improve the pond environment for your fish. The treatment is completely safe for fish, plants, pets, and wildlife.