What's going on here, ozonator?

[Madison Mike]

I was talking to guy on the jobsite the other day. He tells me he has an ozonator in his hot tub, and that he only adds about 1 teaspoon of chlorine every week. No other chemicals added, at all. So, is there "stuff" growing in his spa that he doesn't know about? Will this procedure be OK for a spa? After reading these forums for the last month, I don't want to get in his hot tub. For that matter, I don't want to get in any hot tub until I know what's in it.

 

[zea3]

Personally I would not trust that his hot tub was sanitized with just ozone and a teaspoon of bleach. How often does he use the hot tub, and how long does he run the ozonator? Those with more hot tub experience can give you a more detailed answer, but my gut reaction is stay away from that hot tub.

 

[JasonLion]

Ozone can be used to regenerate bromine. If there is bromine in the tub his approach is at least marginally plausible, though still not a great idea. Without bromine that is a very bad idea.

 

[Isaac-1]

People bathe in all sorts of stuff, some get lucky. Having said that it is hard to saw exactly what is going on with his water, Ozone does make a good supplemental oxidizer for hot tubs, but I would not trust is alone. As to the amount of bleach, if he were to only use the hot tub once per week, showers before using it, and add the bleach when he gets out then covers the tub. Then he may be killing everything in the water with the spike of chlorine and the ozone is keeping it knocked back during the week. He may also have a mineral cartridge system (silver ion) which may also provide some supplemental oxidation which all totalled together might work for him.

Ike

 

[chem geek]

As Jason noted, if he created a bromide bank either by adding sodium bromide after a water fill or by using bromine tabs, then ozone will generate bromine from the bromide in which case the spa may be sanitized and OK. If he doesn't have bromide/bromine, then his spa is not properly sanitized or as Isaac noted, there could be a copper/silver mineral sanitizer that can help control bacterial growth. There is a small amount of residual ozone that gets into the spa water, but it is not supposed to be very much because it can outgas and is an EPA-regulated air pollutant. Also, the ozonator is usually not running 24/7.

Whether a spa gets bacterial growth or biofilms is dependent on many factors so appears statistical. I tracked numerous cases of hot tub itch/rash/lung on another forum and the use of too little or no disinfectant or use of alternative disinfectants appeared to be the primary cause and there were cases that occurred in spas that had ozonators. So just as there are pools that are improperly maintained but don't show algae, you can have a spa that appears OK as well -- that is, you can get lucky.

So to have the least likelihood of getting problems from a hot tub, it is best to maintain a proper disinfectant level at all times (after initially removing any biofilms if it wasn't properly maintained earlier).

 

[Madison Mike]

Thanks for the reply's. Much appreciated. I'm going to talk to my buddy about this the next time I see him.