KollerCraft TOM RP90 Rapids Pro Filter with UV Sterilizer for Aquariums Advanced filtration system for larger aquariums (up to 90 gallons) Processes waste and impurities to keep aquarium water crystal clear and tank inhabitants healthy 18-watt UV (ultraviolet) sterilizer effectively removes unsightly green water and aids in removing harmful parasites Flow rate of 490 gallons per hour (GPH) Suitable for freshwater or saltwater aquariums