An ozone generator also know as an ozonator introduces ozone into the spa water Ozone gas is produced when oxygen is exposed to ultraviolet light and 3 oxygen atoms are bound together instead of the usual 2, this acts as a sanitizer that helps destroys bacteria and viruses present in the spa water.
Although the ozonator system doesn’t eliminate the need for chemical treatment altogether it does help to reduce the amounts of chlorine / bromine needed.
All of the Better Living Outdoors hot tubs have ozonators installed.