Algreen's PressureFlo 1000 Pond Filter with Ultra-Violet Clarifier is the perfect solution to filtration for ponds up to 1,500 Gallons. The PressureFlo Filters includes mechanical and biological filtration helping keep pond water clean and healthy. U.L listed with a 2 Year Warranty (excluding Bulbs). This Pond Filter includes an Integrated 9 Watt UV Bulb preventing formation of algae and making ponds virtually maintenance free.