Chlorine and Ozone - Workable?

[kingdarb]

Hey Folks.  I have a new-ish tub and have been using dichlor as a sanitizer.  I have been thinking of adding a Del ozone system to the tub.  I have read conflicting opinions about how well chlorine and ozone work together.  I am wondering if anyone who knows more about this stuff might have some advice?  I am not likely going to switch to bromine, as my wife has some issues with bromine.

Thanks!

[chem geek]

The answer depends on how much you plan to use the spa.  If you are going to be using it every day or possibly every other day, then there should be no problem.  The issue of ozone reacting with chlorine only becomes a problem when you use the spa less frequently, say only on weekends or perhaps just twice a week.  The daily chlorine demand in between soaks could be 50% or more so you'd have to add chlorine in between your soak.  So the problem is just this extra work.

Ideally if you were able to have a switch to enable/disable your ozonator, then you'd want to turn it on after your soak for around 12 or possibly 24 hours and then turn it off until your just after your next soak.  That way, chlorine will last longer in between soaks.

[Tman122]

I get it, run the ozone between soaks to extend the cleanliness of the water between chlorine additions. Use the chlorine additions to kill the nastys you introduced during your soak.

[chem geek]

No, you've got it backwards at least as far as the timeframes are concerned.  You want to use ozone right after your soak to oxidize the bather waste.  You also add chlorine right after your soak to kill off pathogens in the water, especially those not getting circulated that may be stuck on surfaces.  Because the ozone will oxidize some of the bather waste, you'll use less chlorine doing so.

However, because ozone also reacts with chlorine, you ideally want to turn your ozonator off after some number of hours and then just have the remaining chlorine disinfect the spa in between soaks.  With no ozone, the chlorine will last longer so you won't need to add it as frequently.  Though this is the ideal situation, in practice one doesn't have control over the ozonator so this is why using chlorine with an ozonator really only works out if you are soaking nearly every day because the ozonator will increase chlorine demand to 50% or more daily so chlorine won't last for more than a day or two.