Ozone is an oxidizer not a sanitizer. Bromine ,Chlorine are sanitizers and oxidizers, but they are not that great at oxidizing. Sanitizing is for bacteria and oxidizing is"shocking". You do not really need an ozonator because you can shock with a sanitizer or a non chlorine shock. A ozonator will reduce the amount of sanitizer you need because a lot of what you add is used up oxidizing not sanitizing. Ozonators are more of an automatic thing and anything you add to your spa to help keep it clean is a good idea.
Who's on first?
Or better yet; There are known knowns and known unknowns....