Aquarium Gravel Cleaner - Naturally Maintain a Healthier Tank, Reducing Fish Waste and Toxins (16 fl oz)Introduces healthy, natural bacteria that biologically eliminate excess fish waste, fish food, toxins, odors, and other organic wastes. Extends the time between water changes and vacuum gravel cleanings by eliminating organic waste that accumulates in your aquarium. It also helps correct for overfeeding. Improves water quality and clarity and naturally reduces the build up of toxic ammonia and nitrite as well as problem causing nitrate and phosphate.