The Aquascape UltraKlean 3500 Pond Filter with high-output ultraviolet clarifier and integrated electronic bulb-saver provides pond owners with optimum water conditions and crystal-clear water for ponds up to 3,500 gallons. The unique sponge-free design minimizes maintenance and maximizes efficient mechanical and biological filtration as the UltraKlean Bioballs create small channels by packing together, leaving behind unwanted debris. UV clarifier/sterilizer eliminates single-celled algae commonly referred to as green water. The bulb-saver timer feature allows for bulb on/off customization to save bulb life and provides an ideal time to add water treatments while the Simple-to-use self-cleaning feature allows for the unit to be backwashed in less than five minutes without opening the canister or getting your hands dirty. A cleaning indicator light will automatically remind you when the filter requires backwashing. The Aquascape UltraKlean 3500 Pond Filter comes complete with all necessary fittings and carries a 3-Year Limited Warranty.