Submersible 40 watt Ultraviolet (UV) Light Pond Water Clarifier for use with pumps up to 3000 GPH, in ponds up to 6000 gallons. Kills suspended algae with UV light. Water can be pumped through the UV light and then into a biological filter (sold separately) where debris and dead algae can be trapped and decomposed. When installed correctly, UV lights are very effective at eliminating green water
