A Precision UV System will easily sterilize bacteria (such as e.Coli) and viruses (like cryptosporidium) that chlorine cannot kill. It's why surgical instruments are sterilized using UV light in hospitals. Swimming in drinking quality water is like nothing else. The precise application of UV light to water allows everyone to enjoy a friendly, healthy pool without burning eyes or the smell of bleach. Once you've had the UV experience, you'll never go back!