JUWEL Nitrax reduces nitrate levels in your aquarium, leading to a considerable reduction in algae growth.Nitrax is a biological filter on the containing specialist microorganisms to break down poisonous metabolites (ammonium/nitrite) in your aquarium, thus reducing the danger of fish mortality.Nitrax also reduces algae growth by anaerobically breaking down nitrate, thus supporting the vitality of your fish.Characteristics of JUWEL Nitrax:• Reduces nitrate• Promotes plant growth• Increases the vitality of your fish• Purely biologically active