The most effective way of preventing green water and maintaining optimal conditions in a pond is by incorporating UV sterilization as a part of your pond filtration. The addition of a UV sterilizer/clarifier not only helps control green water, and the suspended algae in your pond, but is an efficient way to control algae while ensuring optimal pond conditions for fish and plants. The SunSun CUV-218 has a unique design which feeds the water through a special helix, meaning the water does not just run through the UV but spins inside, allowing the UV more exposure before the water exits the outlet. This form of sterilizer enables increased efficiency from a more-even exposure of the water to the UV. This improved UV system, the Ultra Violet Clarifier, continues to be a key element of a well filtered clear water system. Unlike other sterilizers, this unit has three inlet / outlet’s – very useful if you want to run the output to a two-fall waterfall, or indeed a waterfall and a filter. The unit comes complete with three stepped hose tails to fit a variety of hose sizes. The UV clarifier also has a transparent center panel enabling you the to check that the UV is fully operational at all times. The SunSun CUV-218 18 watt UV Light Pond Water Clarifier for use with pumps up to 660gph, in ponds up to 5283 gallons. High-performance UV bulb ensures professional power while ease of installation and maintenance make it the right unit for new or existing ponds or water gardens. Included 0.75′′, 1′′, 1.25′′ and 1.5′′ fittings. For peak performance, UV bulb should be replaced after 8,000 hours (about once every 11 months of operation)., ,Power: 18W,Suitable for pond sizes up to 5283 gallon,For use with pumps up to 660gph,Length: 46cm / 18′′,Voltage: 110-120V,18W UV Bulb Included,Suitable for Marine and Freshwater,Translucent End-port to Ensure UV is Fully Operational