Apparently Ozone is a very strong oxidizer, chlorine and bromine are also very strong oxidizers. Given that they are in effect the same thing, why doesn't ozone by itself work as a sanitizer? Is it because the ozone units are too small and not producing enough? What if you were to say hook 3 or 4 units up to your spa - would that prevent the need for additional sanitizer chemicals?

Thanks

The issue with ozone is that it is only present in a certain percentage of the water at any one time. Note that with an ozonator you only need a small amount of residual sanitizer such as chlorine or bromine...

Adding 3+ ozonator units to a spa would have the same effect as constantly adding too much chlorine or bromine. Having so much of an oxidizer like ozone in the water would eat your spa components too... which means your jets, spa cover, anything plastic, pump seals.... and your skin, and you'd have headaches forever just trying to use such an animal.

My favorite combination is an ozonator, with a Spa Frog and .5ppm bromine or chlorine; which is ideal.

To add to Pageup's explaination, Ozone is only effective for a very short time, so it is a contact sanitizer. It won't sanitize all the water efficentially enough to have benefit. Only what it comes in direct contact with, most often before the water even re-enters the spa. Some ozonators are plummed so close to the tub return however that the ozone "outgasses" which is when the ozone leaves the water and becomes airborne. This makes the ozone much less effective since it is no longer in the water, and in concentrations high enough can be harmful to you. Fortunatly, the output of most ozonators out there is so small that even if outgassing does occur, the concentration is so small it is unnoticable and ineffective to your body.