Fluval CLEARMAX is a science grade resin designed to adsorb phosphate, nitrite and nitrate. Removal of these compounds results in crystal clear water, less odours and it reduces themaintenance of your aquarium creating ideal condidtions for fish. • Traps phosphate, nitrite and nitrate • Creates crystal clear water, ideal conditions for fish and plants • For fresh and saltwater aquariums • Treats 300 L (80 U.S. gal.) For filter models: 106, 206, 306, 406, FX5, 105, 205, 305, 405, 104, 204, 304, 404.