Danner 05045 PUV-4000 Pressurized Filter with UV Light for 4000-Gallons Ponds Pressurized filter with UV light for 4000-gallons ponds Features a unique, manually operated agitator for dislodging over 90 percent of the pond residue that accumulates in the filter chamber This patent pending feature is employed during the backwash and rinse operation This integrated system can be conveniently located in or near a pond or patio container 1/2-inch threaded fittings, ball valves for waste line and swivel fitting included