The Aquascape UltraKlean™ 3500 Pond Filter with high-output ultraviolet clarifier and integrated electronic bulb-saver filters ponds up to 3,500 gallons, providing pond owners with optimum water conditions and crystal-clear water. The unique sponge-free design minimizes maintenance and maximizes efficient mechanical and biological filtration. The included biological media packs together tightly, effectively trapping debris. The high-output 28-watt UV bulb eliminates single-celled algae that cause single-celled algae (suspended algae) blooms. A bulb-saver timer feature saves bulb life and provides an ideal time to add water treatments. 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.