Ultra Pure UPAG20 Ozonator for Above Ground Pools up to 20,000 Gallons UltraPure Model # UPAG20 for In Ground or Above Ground Pools with up to 20,000 gallons of water. Ultra Pure gives the most powerful oxidizer available to pool & spa water. 90% of your chlorine or other sanitizing chemicals are used up on organics: body oils, pollution, hair products, lotions, etc. By using the Ultra Pure Above Ground Ozonator for your pool, you will greatly reduce the demand for Chlorine. The Ultra Pure Ozonator will: Break down swimmer waste; perspiration, body oils, make up, hair products, tanning lotions, and more. Improve water clarity Reduce the amount of chlorine sanitizer you use Reduce the amount of Bromine you use Reduce the amount of any other alternative sanitizer you use The Ultra pure ozonator has a UV bulb that breaks down oxygen molecules to combine with other oxygen molecules to produce ozone. The ozonator is connected to your pool and the ozone is introduced into your water while it is circulated and breaks down contaminents.