Enjoy superior water quality for a healthier aquarium inhabitants. Works equally well in marine or freshwater aquariums to remove heavy metals, copper, phenol, ammonia, and other nitrogenous waste. Helps keep pH at a consistently safe range and your water sparkling clear. Fantastic for use with African Cichlids and Discus. Chemi-Pure Elite adds ferric oxide to the original Chemi-Pure formula to also remove phosphates and silicates, making it the only complete choice for filtering any kind of aquarium. Each pre-bagged 6.5 oz Chemi-Pure Elite treats up to 20 gallons; 11.74 oz Chemi-Pure Elite unit treats up to 50 gallons. Each extra-large 46.96 Grande Elite nylon bag treats 175-200 gallons. Remains active 4-6 months.