Ozonator - Good or Bad?

[Spoiledrotten]

I did a search for the Ozonator and found quite a few post regarding, but they were very old post from 2005 - 2009.

I'd like some up to date comments on the good and/or the bad of these things. I've recently developed a rash that looks like chemical burns, so I'm looking for another way to keep the water sanitized without using so many chems. What would you suggest?

I've tried using the test strips but I'm obviously doing something wrong. I'm most likely over sanitizing my water. I also read that Ph too high will also cause skin irritation. I've got so much to learn about this.

[chem geek]

An ozonator does not provide a residual fast-acting disinfectant in the bulk spa water.  That's what chlorine or bromine or Baquacil/biguanide/PHMB or Nature2/MPS is for and those four are the ONLY EPA-approved disinfectants for spas.

You should probably get a proper test kit.  The Taylor K-2006 kit is the best and has a very accurate FAS-DPD chlorine test with it.  That way, you can properly maintain your chlorine or bromine levels as well as pH and Total Alkalinity (TA).  Though you can use the K-2006 with bromine (with an adjustment factor), there is a K-2106 kit for bromine as well.

As to whether an ozonator is worth it, if you use the spa a lot, such as every day or two, or if you are using bromine, then an ozonator can help because it oxidizes bather waste and reactivates bromine, but if you are using chlorine and use the spa infrequently, only once a week or so, then an ozonator will end up reacting with chlorine costing you more and requiring you to add chlorine even more frequently.  So a key question is how often you are using your spa.  Also tell us more about what you have been using to disinfect your spa -- are you using chlorine or bromine?  What product are you using, such as Dichlor for chlorine or bromine tabs and whether you started by adding sodium bromide, etc.

[Spoiledrotten]

Chem Geek,

Thanks for the quick response. History: I'm using chlorine for sanitation. I've been putting about 1 tablespoon of chlorine in the spa after each use, which is just about every evening and includes two people, the little wife and I. We generally soak for 1.5 hours after dinner. It's a three seater spa, holding about 210 gallons according to the specs. About once a week, I put in a tbsp. of Spa Shock. I've tried using the test strips, but the colors seem to be way off. I was developing a rash (like a chem burn) for the last few weeks, so I did some searching on this site and found that a high Ph could cause that problem.
I dumped the spa and refilled it earlier this week so I'm basically starting over with the chems. I put about 3 tbsp. of chlorine in the water to start with.
After decided that the Ph is way high yesterday, I turned on the pumps, blowers and put about 4oz of Ph decreaser in, waiting about 30 minutes and tested again. Still seemed way high so I put 4-5oz more in and left to churn about 30 more minutes. According to the test strip chart, the Ph looks good, but the chlorine level is high and the TA seems to be low. Is too much Chlorine a problem or will it quickly dissipate? I don't know what other information to give you at this time, but again, thanks so much for the help.

There's got to be an easy way to measure chems in the spa.... I believe the first step will be to purchase that kit you linked me to in your first response.

[chem geek]

Assuming you do not have an ozonator (which is why you were asking about it), two people soaking for 1-1/2 hours is 3 person-hours of bather load.  If your spa was hot (104ºF), then that would require 10-1/2 teaspoons of Dichlor to oxidize the bather waste, not the 3 teaspoons (1 tablespoon) that you used.  I assume that you weren't soaking at 104ºF since you can't do that for 1-1/2 hours.  What was your water temp?  With a lower temp, you sweat less, but even so I'd bet you still needed at least 5-8 teaspoons of Dichlor so you have been underdosing chlorine.

Do you measure the chlorine level before your soak and if so has it ever been zero or very near zero?  If so, then it's more likely that when the chlorine got to zero, bacteria grew and the irritation you have could be folliculitis.  What is the brand for the "Spa Shock" product you are using and are there ingredients on the label?  I suspect it might be non-chlorine shock (does it say "potassium monopersulfate" or "potassium peroxymonosulfate"?).  Non-chlorine shock can be irritating, mostly due to the minor component "potassium persulfate".  See this link and try to figure out if your rash is a chemical reaction or a bacterial infection.

As for your TA, low may be OK if your pH tends to rise or is at least not dropping -- even 50 ppm is OK.  For additional pH stability at a lower TA, you can use 50 ppm borates, say from Proteam Gentle Spa, or from boric acid, or from a combination of 20 Mule Team Borax with dry acid (each added separately half at a time).

With your very high bather load (frequent long soaks in a smaller tub) you would probably be better off using the Dichlor-then-bleach method.  Also, in your situation an ozonator would indeed be very helpful so that you don't need to use as much chlorine as you should be using (not what you are doing today -- an ozonator might let you use roughly the chlorine amount you are currently using, but your tub will be safer since the chlorine won't get to zero).

[Spoiledrotten]

Wow! Lots of great info, Chem Geek. Much appreciated. About the only question I can give you an answer to right now, since I'm not at home is the temp. We don't like the "hot" soaks so we keep them temp at around 95*. It's perfect for relaxing for longer periods of time. Keeps the body toasty warm while the cool breeze is whipping around our heads.

The spa shock is non-chlorine type as that is what I asked the little wife to buy just after we got the tub and after I started reading some posts here. Just not sure what brand it is.

As far as the chlorine amount, it's probably best to be a little over chlorinated than under chlor? I think I also read somewhere that skin specialist sometime prescribe their patients to chlorine baths to help whatever skin condition they have.

Again, thank you so much for taking your time to explain things to me and to ask questions about the condition and products I use. I ordered the test kit that you recommended yesterday, so I'll be able to test with hopefully, better results. I also took a sample of my water to the local pool supply and found out that the Ph was low and the TA was also low so the computer printout suggested 5oz of Alkaline increase. I had also added too much chlorine when I refilled with fresh water, so she said I should not add chlorine for about two weeks.

[TwinCitiesHotSpring]

Wow! Lots of great info, Chem Geek. Much appreciated. About the only question I can give you an answer to right now, since I'm not at home is the temp. We don't like the "hot" soaks so we keep them temp at around 95*. It's perfect for relaxing for longer periods of time. Keeps the body toasty warm while the cool breeze is whipping around our heads.

The spa shock is non-chlorine type as that is what I asked the little wife to buy just after we got the tub and after I started reading some posts here. Just not sure what brand it is.

As far as the chlorine amount, it's probably best to be a little over chlorinated than under chlor? I think I also read somewhere that skin specialist sometime prescribe their patients to chlorine baths to help whatever skin condition they have.

Again, thank you so much for taking your time to explain things to me and to ask questions about the condition and products I use. I ordered the test kit that you recommended yesterday, so I'll be able to test with hopefully, better results. I also took a sample of my water to the local pool supply and found out that the Ph was low and the TA was also low so the computer printout suggested 5oz of Alkaline increase. I had also added too much chlorine when I refilled with fresh water, so she said I should not add chlorine for about two weeks.

just an FYI, chlorine will drop in effectiveness at around 25% per day + if you factor in heavy usages than that 2 week number she gave you is nowhere near accurate unless you dumped in half a bottle, which I'm assuming you didn't.  Also regarding ozone, one thing to remember is that you need circulation for the ozone to work properly, if your spa is not equipped with a 24hr continuous circulation pump but rather "filter cycles" I would boost up your cycles to run more often otherwise you've wasted money on an ozone because it will not properly function

[chem geek]

So at the 95ºF the amount of chlorine you will need to add after a soak will be less than the full amount I gave.  Unfortunately I can't give you a good idea of what that amount would be, but it's probably still at least half the full amount and that's still a lot more than you had been using.  The right amount for you to add is whatever it takes such that you have a 1-2 ppm FC residual at the start of your next soak.  And yes, it's better to be higher rather than lower -- you really don't want the chlorine to get to near-zero for an extended length of time (more than an hour or two).  If you overshoot and start a soak with a higher chlorine level, you may notice more smell but it's not a problem unless it's very high (something like 10 ppm or higher, assuming you've got some CYA in the water already from initial Dichlor use).

If you use Dichlor-only, then you'll be needing to change the water sooner.  If I assume your 1.5 hour soaking is equivalent to 1 hour of soaking at a hotter temperature, then that's 2 person-hours per day.  The Water Replacement Interval (WRI) would then be (1/3) x (Spa Size in Gallons) / (# of bathers per day soaking 20 minutes) = (1/9) x (Spa Size in Gallons) / (# of bather-hours per day) = (1/9) x (210) / 2 = 12 days so not very long at all.  This is because the spa is small and your bather load is high.  If you were to use Dichlor-then-bleach, then you should be able to go at least twice as long, so 24 days or around one month before a water change and when you do need to change the water it will be in better shape compared to Dichlor-only.

How long have you been going between water changes and how does the water look after a few weeks of using the spa after a fresh water change?

[Spoiledrotten]

Great info, CG! As far as water changes, I just changed it for the first time since I got the spa in early September of this year, so I went about 2 full months on one tub of water. I figure that with only 210 gallons, I can easily change the water every month or two. I'm kind of a "germ aware" person, so keeping enough chlorine in the water is important to me. So far, since changing the water, I've kept the Chlor a little higher than I probably need to. I thought the person at the local pool supply was a little off with her suggestion of going two weeks before adding Chlorine again. I've already added after a couple of days. Don't want to soak in bacteria if I can help it.

Thanks for the formulas, too. I had no idea that the water would need to be changed every 12 - 24 days. That's not much better than soaking in the tub in the house. :-) Oh well, I guess I'll play that part by ear and watch the tests closely.

My TA seems to be right in line, with Ph pretty close. I've been using some test strips that came with the spa, so I'm not too confident in them. My new test kit that you suggested is supposed to be delivered this Wednesday, so maybe I'll be a little more on top of accurate readings, going forward.

And your other question; my water was starting to look cloudy around the 2 month mark.