Why does an ozonator allow lower bromine levels?

[d.sebens]

If ozone isn’t a sanitizer and you are using a 3 step bromine maintaining a constant sanitizer why does ozone allow a lower level?  Will sanitizer level drop during use and ozone will help boost it up?  That doesn’t completely make sense since both the bromine tabs and the ozone are constant additions. What am I missing?

[RDspaguy]

Who said it allows for lower bromine levels?

Ozone is an oxidizer, and it will destroy pathogens it comes in contact with. But, since it is taking water from a dirty tub, running it through a 3/4" hose with ozone, and returning it back to the dirty tub, it cannot be considered a sanitizer. That said, on a 24/7 circulation system typical flow rates are about 8-10gpm or so, so it will "turn over" (move the volume of the tub) once every hour or less. 4 or 5 turnovers will move 99% of the actual water (and pathogens) through the ozone injection system. This theoretically decreases the volume of the contaminants for your bromine to react with, so there will be less bromine needed.

Sounds great, right? Unfortunately, the bromine, as a residual in the water, will react with the contaminants before they reach the ozone.

Ozone will also oxidize bromide into bromine to a small degree, and burn off that bromine to an even smaller degree. So you probably won't see much of an effect on the overall bromine levels.

Ditch the floater (my recommendation anyway) and add chlorine after use and you may see a bit of the benefit of ozone, but not a lot.

Ozone is best with chlorine, as it burns off combined chlorine (the stuff that stinks) quickly and free chlorine a little slower. It also doesn't necessarily reduce the amount of chlorine you use, it just gets rid of it after it is done doing its thing, so leaves you with a "low chlorine" tub at the time of use if you treat after use.

[d.sebens]

7 hours ago, RDspaguy said:

Who said it allows for lower bromine levels?

Ozone is an oxidizer, and it will destroy pathogens it comes in contact with. But, since it is taking water from a dirty tub, running it through a 3/4" hose with ozone, and returning it back to the dirty tub, it cannot be considered a sanitizer. That said, on a 24/7 circulation system typical flow rates are about 8-10gpm or so, so it will "turn over" (move the volume of the tub) once every hour or less. 4 or 5 turnovers will move 99% of the actual water (and pathogens) through the ozone injection system. This theoretically decreases the volume of the contaminants for your bromine to react with, so there will be less bromine needed.

Sounds great, right? Unfortunately, the bromine, as a residual in the water, will react with the contaminants before they reach the ozone.

Ozone will also oxidize bromide into bromine to a small degree, and burn off that bromine to an even smaller degree. So you probably won't see much of an effect on the overall bromine levels.

Ditch the floater (my recommendation anyway) and add chlorine after use and you may see a bit of the benefit of ozone, but not a lot.

Ozone is best with chlorine, as it burns off combined chlorine (the stuff that stinks) quickly and free chlorine a little slower. It also doesn't necessarily reduce the amount of chlorine you use, it just gets rid of it after it is done doing its thing, so leaves you with a "low chlorine" tub at the time of use if you treat after use.

Some guy on here said it!  So why ditch the floater?  What should bromine readings be approx at beginning of soak?  If I just used bleach would I be doing a full shock everything or just enough to get it to the correct level before the next soak?

[RDspaguy]

Hahaha! 🤪 I forgot about that. I was quoting other sources. I have since learned, from others experimenting with bromine and ozone, that it has no noticeable effect on the bromine residual. And, as far as anyone can tell, does not significantly convert sodium bromide to bromine. 

According to ozone manufacturers, it allows for lower levels of bromine. Which means that, in laboratory conditions and with whatever test setup they have (not a spa) it reduces pathogens in the water by a significant degree. 

10 hours ago, RDspaguy said:

This theoretically decreases the volume of the contaminants for your bromine to react with, so there will be less bromine needed.

This is their logic.

10 hours ago, RDspaguy said:

Sounds great, right? Unfortunately, the bromine, as a residual in the water, will react with the contaminants before they reach the ozone.

This is the conclusion I have come to since writing that post. 

Thanks for pointing that out. I should edit that.

[d.sebens]

So I have a thing of bromine tablets and floater.  Is there anything against using it till I run out then switch over to manual application of chlorine?  I don't want to waste it.  I had bought the stuff before reading on here so that's what I have now.

[RDspaguy]

No problem. Bromine tablets are mostly chlorine anyway. I don't recommend them due to the low ph and the tendency to end up in or in front of the filter well, which puts high concentrations of acidic chemicals through your equipment. 

[waterbear]

I prefer 3 step bromine (add sodium bromide to create a bromide bank, oxidize with chlorine to activate, and use a floater to maintain the bromine level)  in a tub over chlorine since it means that, once properly adjusted, sanitizer levels stay fairly constant. RDSpaguy is correct that ozone is better with chlorine but there is no reason that you can's use bromine with ozone. He is also correct that bromine tablets contain chlorine along with an organic bromine source. The bromine refreshes the bromide bank and the chlorine oxidizes it into hypobromous acid. If yo live in Canada you can no longer purchase sodium bromine unless it is in a 'one step' bromine product (sodium bromine and either dichlor or MPS), which can be used initially to create your bromide bank. Tablets are slow dissolving and it can take a few week for a bromide bank to develop. Until is does your tub is still sanitized because of the chlorine present in the tablets so just maintain the sanitizer at a 4-6 ppm level and it's all good.

pH of Bromine tabs is around 4 so it on the acidic side but the pH of MPS and trichlor are both lower.  I used 3 step bromine for years  when I had a stand alone hot tub so I have personal experience in using it (I now have a pool with attached spill over spa and use a SWCG). While it is true that a floater can get caught in front of a skimmer they usually don't in a spa because the circulation pumps that runs either continuously or several times a day tends to keep the floater in movement. The floater getting caught is more likely in a pool because the movement of water into the skimmer is stronger and the flow from the returns much weaker in a pool when compared to a spa.

[d.sebens]

So @waterbear if I do three step should I shock once a week or still after every soak.  If i boat it after a soak should it be a whole shock or less?  I’ve been doing to about 8ish ppm when I get out.  When the kids are in with us it tends to make it to 0ish ppm. I am currently at about 3 ppm initial, still tuning the opening of the floater. 

[waterbear]

maintain 4-6 ppm  bromine by adjusting the floater. This takes trial and error. Make small adjustments in the foater and vie it several days to stabilize in between. Once you get it adjusted you should not need to make any changes. If bromine goes too high then just take it out for a day or two.

Shock to raise the bromine above 10 ppm (10-15 ppm range is good) once or twice a week, depending on spa usage. IF the spa is not used and bromine levels are in range then don't shock, it's not needed. The purpose is to oxidize any organics in the water that people put in. Every bather adds feces, urine and sweat to the tub no matter how clean they THINK they are when they go in. Fun Fact, you sweat when in the tub because of the hot water and the chemical makeup of sweat is almost identica to urine!