The Fluval G3 Nitrate Cartridge is for use with the Fluval G3 advanced filter and will remove up to 13000 milligrams of nitrate ion in fresh water aquariums. Nitrate concentration should not exceed 20 mg/L in freshwater aquariums. Planted aquariums require approximately 5 mg/L of nitrate as a source of nitrogen for healthy plant growth. Nitrate is irreversibly trapped and bound and will not leach back into the water. The continuous use of the G3 Nitrate cartridge in aquariums with persistent nitrate problems is an effective solution against nitrate accumulation. If used as a quick solution to reduce elevated nitrate concentrations the cartridge can be removed once levels have normalized and then stored until required.