Keep your Fluval U3 Underwater Filter working effectively and help to control green water and algae growth with Fluval U3 Poly/Clearmax Filter Cartridge. Fish waste， uneaten food and other organic matter can build up in your aquarium water， causing algae growth and increased phosphate， nitrite and nitrate levels. Raise these levels too much， and they can be harmful to fish. This filter cartridge helps to absorb and trap these pollutants， protecting your aquarium and those who call it home. Designed for the Fluval U3 Underwater Filter， Fluval U3 Poly/Clearmax Filter Cartridge supports crystal clear water， helps to control odor and works to reduce overall aquarium maintenance.

HAZARDS TO HUMANS: Always disconnect appliances in the aquarium from the electrical supply before placing hands in the water， before putting on or taking off parts， and whenever the filter equipment is being installed， maintained or handled.Following a routine maintenance schedule will result in a healthier aquarium and extend the life of the filter. Fluval filters have been designed to facilitate these tasks as they can be done within a matter of minutes. For best results， please follow our maintenance schedule recommendations.