The Laguna PT1671 is a UV pond clarifier for ponds up to the following size:
The Laguna UV Pond Clarifier 14W - Up to 1000 Gallons contains a 14 watt Ultra Violet (UV) lamp. This Laguna UV sterilizer will eliminate green water from your small to medium sized pond, meaning that it clarifies the water. This PT1671 clarifier has a LED light that indicates when the UV lamp is on. This clear pond water sterilizer comes with 2 universal Click-Fit connectors that fit 3/4, 1, and 1 1 1/4 inch hosing.
The Laguna PT1671 specifications: