Matrix Carbon is a truly unique activated carbon. Matrix Carbon has a very low ash content as indicated by its minimal impact on pH. Even when added to distilled water; it does not raise pH above 7.0. While all carbons contain phosphate; regardless of false claims to the contrary; Matrix Carbon has the lowest leachable phosphate content of all major carbon brands tested. It out-performs other best grade carbons. It is very clean and nearly dust free. Can be used in many applications; including power filters; canister filters; and wet/dry filters & sumps. For more information on chemical filtration; please see our article on Aquarium Filter Maintenance.