Polish AC Activated Carbon is highly efficient at removing harmful pond contaminants such as, tannins, ammonia, nitrate, nitrite, chlorine, phosphates and more. Polish AC is super-heated to "activate" the carbon and provide a high level of porous surface area for increased efficiency. This process allows the contaminants and particles to stick or become absorbed by the activated carbon. Polish AC is apporiately named because it polishes the water and helps add a briliant shine to any pond environment. Polish AC is not ment to be a problem solver but a preventive and additive to keep potential problems at bay. This 5 pound pack of activated carbon can treat a 1000 gallon pond for 3 months.