The UltraPure™ Automatic Water Cleaner™ is an Ozone Generator.

Air, containing oxygen (O₂) passes over an ultraviolet light. The ultraviolet rays break down some oxygen molecules which recombine as ozone (O₃).

The ozone-containing air is passed into the pool or spa's filtration system and into the water. The ozone in the water now proceeds to break down organic compounds (lotions, oils, sweat, urine, etc.), eliminating them from the water.

Since the only element added by the ozone generator is oxygen, no obnoxious compounds are created (like chloramines), and many by-products simply 'gas-off'.