TetraPond GreenFree Clarifier UV2, 18 Watts, Ponds up to 4400 Gallons (Discontinued by Manufacturer) UV Clarifier destroys reproductive ability of suspended algae Algae clump together in particles large enough to be removed by filtration Remove heavy algae blooms within 5 days Includes fittings for tubing 1", 1 1/4", 1 1/2" ID For ponds up to 4400 gallons, max flow of 2200 GPH