Ultraviolet is a proven dependable and effective method of controlling algae and harmful bacteria without leaving any residuals in the water. Aqua Ultraviolet utilizes the highest quality components designed to work perfectly together to maximize kill rates and ensure ease of installation and maintenance. There is no need to by pass or adjust your water flow. Our units will perform at or above stated levels throughout the life of the lamp.Used as a sterilizer, the Classic 15 Watt UV is the premium choice for 200-500 gallons of fresh water or up to 75 gallons of salt water.Used as a clarifier, the Classic 15 Watt can treat up to 2000 gallons of fresh water that has 50% to 75% plant coverage.Aqua Ultraviolet Sterilizers will clear your water in 3-5 days sometimes overnight and keep it that way. Performance is guaranteed when sized, installed and operated according to our instructions.