Hot Tub Forum
Original => Hot Tub Forum => Topic started by: 999 on February 10, 2012, 11:40:03 am
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After owning my hot tub for just over 3 months I changed my water and took the opportunity to change from Bromine to granular Chlorine (dichlor 55%).
Straight away I noticed that the smell of chlorine is much better. (personal preference I know)
I need to establish a regular routine dosing with chlorine. It is difficult to know how much to dose and how long it will last.
My tub holds 1700 litres or 450 US gallons and I have an ozonator. We use the hot tub about three times per week, but most of the time it is just me and my wife. Our young kids sometimes get in but not for long.
On the first day of my new water I added 5 teaspoons of granular chlorine and checked the level soon after and found it to be 5 ppm. It then took 24 hours to heat up.
On the second day it was 1-3 ppm.
On day three it was 0. Although we intended to use the hot tub I did not want it to remain at 0, so added 3 teaspoons. (maybe that was too much) This took my level up to 3-5 ppm. About an hour later two of us used the tub. When we got out i threw in another 1 teaspoon. I had planned to does it afterwards but put in a half hearted 1 teaspoon, considering I had already put 3 in earlier.
I don't want to add to much, as this will increase my cyanuric acid levels and reduce the life of my water, but I don't want it going to zero either.
I have obviously got to get into a routine of dosing at the right amount to get me through a couple of days, but also like the idea of dosing after I get out.
I have searched the web for a dosing routine, but there seems to be no hard and fast rule.
I would be interested to know the routine that works for those that use chlorine/dichlor.
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i'm sure you'll get many differing responses on this, but i'll throw my 2 cents in anyways. our customers that rely on dichlor generally use about 6 teaspoons as a regular weekly dose. this will vary based on the size of the tub. as i understand it you want to shock to a level 10 once a week. we also ask that they use smaller doses during the week after soaking to maintain a level (usually 1 teaspoon per person). leisure time makes a cool new product called replenish that you could also use after soaking (85% non chlorine shock/15% chlorine). make sure you flush with spa system flush periodically or you'll find your demand going up due to contaminants in the plumbing.
in almost all cases you'll find that the ph drops when using this method. make sure you test and adjust it every week. powdered spa up (identical to baking soda) will be what you normally need.
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Not sure what spa you have circ pump or not? But get and use one of those mineral cartridges they work well with chlorine and ozone. I also like mentioned find it better if your gonna add chlorine do it after use, that way your not sitting in freshly chlorinated water. While usage varies I add 1 to 2 tblspns of chlorine once a week depending on use shock with 2 tblspns using a non chlorinated shock once a week. Keep PH/alk in check. Thats with a couple of kids and 2 adults at various times.
I do nuke with chlorine at least once a month to a higher ppm. I will also do this before a water change to help clean the pipes out.
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Thanks both. ..... Jacuzzi Jim, i have a Jacuzzi J230CD. It does have a circulation pump. Do you add your chlorine just once a week then?
I have been using non chlorine shock with bromine so intend to use it once a week with chlorine.
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If you weren't using an ozonator, then I could give you a rough rule-of-thumb which is that for every person-hour of soaking in a hot (104ºF) tub, it takes 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize the bather waste. These amounts are independent of spa size. After that, the FC level drops by around 25% every 24 hours.
With an ozonator, this all changes, but how much depends on the strength of the ozonator and on your soaking pattern. For a typical ozonator and bather load, an ozonator cuts down the chlorine demand during the soak by about half, but it also roughly doubles the chlorine loss in between soaks (after bather waste is oxidized) to around an FC drop of 50% every 24 hours.
If you have a fairly regular pattern of soaking, then I would just adjust the amount you add after each soak such that you have a 1-2 ppm FC measured residual at the start of your next soak. For your sequential daily soaks, that would be one amount to add, while for your last soak with a gap a few days before the next soak, you would need to add more unless you wanted to add chlorine in between soaks.
If you wanted to avoid as much buildup of CYA, you could use some non-chlorine shock along with chlorine after your soaks (e.g. Replenish that flyonthewall mentioned) or you could use bleach instead of Dichlor once your CYA is at 30-40 ppm or so, BUT if you use bleach then your water parameters need to be different in order to easily maintain pH (i.e. you need your TA lower at 50 ppm or even a bit lower and you should use 50 ppm Borates). If you use Dichlor-only or a Dichlor/MPS mix, then this is net acidic so you need a higher TA (usually 80 ppm is OK) for the pH to be stable, but over time your TA will drop so you'll bring that back up with some baking soda every now and then. With the bleach method, the TA doesn't change once you get to reasonable pH stability.
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Thanks both. ..... Jacuzzi Jim, i have a Jacuzzi J230CD. It does have a circulation pump. Do you add your chlorine just once a week then?
I have been using non chlorine shock with bromine so intend to use it once a week with chlorine.
Pretty much just once a week, like I said a lot depends on use but yes once a week does work. I test once a week if that as well. After you get it down and figure out what works best for you is the key. Every "body" is different from how much you sweat to how long you stay in. I also don't shower every time before I get in. Now if I have been out weedwacking the property for the last few hours than yes, but daily after work as a sales guy no. Same with the kids during the Summer with sunblock and what not really depends with them, most of the time they just jump in and things are fine.
Biggest thing I tell people is don't sweat the small stuff, use your eye's as well as your nose and after awhile you will be able to tell if things are going good or going bad but don't neglect it either!
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I'm only on day 5 of using chlorine (having changed from bromine) and seem to be struggling.
My chlorine demand seems high. I have already put 12 teas spoons in. (or 4 tablespoons) and on two mornings I have found that my readings are zero. My wife and I have only used the hot tub once.
Day 1 put 5 tea spoons bringing level up to 3-5 ppm
Day 2 didn't put anything in and level was 1-3 ppm
Day 3 level was 0 ppm so put in 3 tea spoons, used the tub then put in another 1 tea spoon
Day 4 level was 2 ppm so i added 1 tea spoon to bring it up to 3 ppm
Day 5 level was 0 ppm, so I have added two tea spoons (we intend to use it tonight so will add another 2 tea spoons after)
I am fairly certain that I don't have a bacteria problem considering that I run the tub successfully for three months on bromine and then used Swirl Away before the water change.
I know that I have a Coroner Discharge Ozonator. This was an optional extra for my tub. Is it this that is driving my chlorine down.
At this rate I will be using about 19 tea spoons per week and that is with low usage (twice). It wont take long for my CYA to build up and then need a water change. I could hit 100 CYA in 6 weeks.
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Day 1 put 5 tea spoons bringing level up to 3-5 ppm
5 teaspoons in 450 gallons would be 7.7 ppm FC so if you measured the chlorine level before and shortly (say within 10 minutes with the circulation pump on) after dosing and it only went up 3-5 ppm, then something is wrong, possibly with your measuring spoon. Are you using an accurate test kit or are you using test strips?
I know that I have a Coroner Discharge Ozonator. This was an optional extra for my tub. Is it this that is driving my chlorine down.
At this rate I will be using about 19 tea spoons per week and that is with low usage (twice). It wont take long for my CYA to build up and then need a water change. I could hit 100 CYA in 6 weeks.
If you don't have bacterial growth or biofilms, then it could be the ozonator that is reacting with a lot of chlorine. Typical ozonators increase chlorine demand to around 2 ppm FC per day. 19 teaspoons per week in 450 gallons would be about 29 ppm FC per week or about 4 ppm FC per day. 2 people soaking for 30 minutes (so 1 person-hour) would consume around 3-1/2 teaspoons of Dichlor so the rest of the demand is 3.4 ppm FC per day which seems high even with an ozonator though I suppose is possible if your ozonator is powerful and on a lot. If you turn off your ozonator, that would tell you if it is the cause of your more rapid chlorine loss.
As for the buildup of CYA, note that most chlorine spa users use only Dichlor and just live with the fact that they have to change their water sooner than they otherwise would. You could completely avoid that problem by switching to bleach after the CYA level gets up to 30 ppm or so, BUT to use bleach you have to take other steps to have the pH be more stable (namely, have a low TA of 50 ppm and use 50 ppm Borates). Also, this won't solve the chlorine demand problem you have that may be due to the ozonator.
An ozonator is more appropriate for spas used more frequently, every day or two, or for bromine spas to keep a bromine residual without needing bromine tabs, though the ozonator needs to not be too strong or else the bromine level will be too high.
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My ozonater is hard wired into the control box and good seem s to be on 24/7. There isn't a switch to turn it off.
As for my initial dose of 5 teaspoon. It was on the high side, so could have been higher than 5.
I do use Insta test strips that seemed fine with using bromine but i do rely on them to give an accurate reading. If i get an extreme reading i take another with some Jacuzzi strips. If they read the same them i figure it is correct.
Used the tub last night, two of us for 40 minutes. Before we got in there was 1ppm and i added two tea spoons when i got out. This morning, 11 hours later it was reading 3ppm. Hopefully there wil still be something left by this evening.
I know it is early days but if i am going to be constantly adding chlorine and a lot of it, i may change back to bromine and just put up with the smell.
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My ozonater is hard wired into the control box and good seem s to be on 24/7. There isn't a switch to turn it off.
As for my initial dose of 5 teaspoon. It was on the high side, so could have been higher than 5.
I do use Insta test strips that seemed fine with using bromine but i do rely on them to give an accurate reading. If i get an extreme reading i take another with some Jacuzzi strips. If they read the same them i figure it is correct.
Used the tub last night, two of us for 40 minutes. Before we got in there was 1ppm and i added two tea spoons when i got out. This morning, 11 hours later it was reading 3ppm. Hopefully there wil still be something left by this evening.
I know it is early days but if i am going to be constantly adding chlorine and a lot of it, i may change back to bromine and just put up with the smell.
Some here will prolly disagree, but you don't always have to have a chlorine reading 24/7 just be sure to hit it once or twice a week and you should be fine. And like you said if your constanlty adding chlorine to keep a level up might as well go back to bromine in my opinion. Thats exactly why I like ozone and proclear (nature2 cartridge) And if for now you want to error on a safe side just add 1 tblspn or less of chlorine after use. You will be fine! Also your ozone is not on 24/7 anytime you hit a main pump btn your ozone will shut off and then come back on after the pumps have been shut down for awhile. Also test strips are not quite as accurate as a test kit with the drops.
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I don't think i could use the cartridge that you mention because my filter doesn't have a centre section that comes off. It is fixed.
I am encouraged to know that there doesn't have to be a constant reading of chlorine.
My ozonator is always bubbling, even with the pump on.
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I don't think i could use the cartridge that you mention because my filter doesn't have a centre section that comes off. It is fixed.
I am encouraged to know that there doesn't have to be a constant reading of chlorine.
My ozonator is always bubbling, even with the pump on.
You can just lay the cartridge in the basket as long as it has some water flow across it it will work. Worth a shot.
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What 'basket' are you referring to. Is this the netting bag in front of the filter oe do you mean behind the filter panel alongside the filter.
If i was to use one of those cartridges as well as ozone, i presume you still use chlorine but less if it?
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Just read the instructions for Nature2 and it says you have to use MPS with it to work. That is another addition that i don't really want to keep adding. I will see how i go with chlorine for the next week. If it proves problematic I will go back to Bromine.
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Sorry I was thinking older J-230. You can just put the nat 2 in the netted bag. MPS is basically your shock which you will be using in conjuction with chlorine. Some people will use MPS (shock) after each soaking as well. and chlorine once to twice a week. Really varies on use and number of people.
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It sounds like your ozonator is overpowered, especially for your low use of your spa. If you use Nature2 with MPS then at least the ozone won't react with the MPS so it should last longer. You'll only need to use chlorine once a week or so as a shock to help keep the water clear. And you won't need to worry about CYA buildup. Sounds like it might be the right approach for you. I'm not sure why you are concerned that this is something else you need to add -- the MPS is used in place of chlorine, not in addition (except for the occasional chlorine shock). Nature2 with MPS is and EPA-approved disinfectant. You shouldn't smell any chlorine or bromine smell nor any disinfection by-products.
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That is a genuine consideration. I will seriously give it some thought.
My brother-in-law has the exact same model of hot tub. It was because of using his that i bought mine.
He uses a system called Bayrol Sparocular and a liquid activator . Once a week he shocks with Spa Lite sachets . He seems happy with this odourless system but it seems quite expensive especially the weekly sachets .
Have any of you heard of or used this.
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Correction ....... Bayrol Bayroclar Spa
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According to the Bayrol Chemical Reference Manual 2009 (http://www.bayrol.com/fileadmin/user_upload/bilder/news/BAYROL_Chemical_Reference_Manual_2009.pdf), the system is probably a combination of Polyquat and hydrogen peroxide with the latter used for shocking (activation) and often referred to as "active oxygen". Hydrogen peroxide is not approved by the EPA as a disinfectant for pools or spas but it is approved in Australia. However, the level of hydrogen peroxide needed for disinfection can be irritating to some people. It's an option you can try if you want to. Bayrol is normally a brand sold in the U.K. whereas in the U.S. the brands are from BioLab such as BioGuard for pools and SpaGuard for spas.
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Jacuzzi Jim, You may be right with regard to the ozone shutting off when the main pump is on. I remembered what you said when I was sitting in it the other night. There seemed to be small bubbles coming out of the outlet with the pump on but when it switched off and we sat there in the still water I noticed that the speed and size of the ozonator bubbles increased, so maybe it does change with the pump being on or off.
Going to persevere with chlorine for now and see how it goes. (Did my MPS weekly shock today as well)
When I check the chlorine level in the morning and if it is zero, but we plan to go in it in the evening would you add some chlorine for the day (1 tea spoon) and then add some more after use or would you just add it after getting out?
Also, how much do you add after it has been used. Do you add a certain amount per person?
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This forum would really benefit from an edit button.
Jacuzzi Jim, you are probably the wrong person to ask if you are using Nature2 as well. I was thinking of those using just chlorine.
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This forum would really benefit from an edit button.
Jacuzzi Jim, you are probably the wrong person to ask if you are using Nature2 as well. I was thinking of those using just chlorine.
chlorine 1-3x per week depending on use, and MPS/Shock once a week is a routine that works well imo....I personally do not like Shock after each use because MPS is commonly known to irritate skin more than all of chemicals you add to the spa...Nature2 is fine but if your considered a "heavy user" I'm not sure it will as beneficial
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This forum would really benefit from an edit button.
999, there is a Modify button for each post that you enter where you can go back later and edit the post. The modify button is in the upper right corner above the post that you want to edit. Hope that helps!
Also, I would encourage you to try the Nature 2 Cartridge with the Chlorine and MPS. Many of my customers use that, and it works great, keeps it simple, and you can really cut down on the amount of chlorine you use by using the MPS with the Nature 2. Its worth trying at least imo!
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This forum would really benefit from an edit button.
Jacuzzi Jim, you are probably the wrong person to ask if you are using Nature2 as well. I was thinking of those using just chlorine.
chlorine 1-3x per week depending on use, and MPS/Shock once a week is a routine that works well imo....I personally do not like Shock after each use because MPS is commonly known to irritate skin more than all of chemicals you add to the spa...Nature2 is fine but if your considered a "heavy user" I'm not sure it will as beneficial
Could you explain what you mean by "chlorine 1-3x per week depending on use"
Are you saying you get the level up to 1-3 ppm, or are you adding 1 of something three times per week.
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This forum would really benefit from an edit button.
999, there is a Modify button for each post that you enter where you can go back later and edit the post. The modify button is in the upper right corner above the post that you want to edit. Hope that helps!
Also, I would encourage you to try the Nature 2 Cartridge with the Chlorine and MPS. Many of my customers use that, and it works great, keeps it simple, and you can really cut down on the amount of chlorine you use by using the MPS with the Nature 2. Its worth trying at least imo!
Doh.... :o yes I see the modify button now, I hadn't noticed that before. That will be useful in future.
Nature2 recommend using it with MPS. What would the routine be if used with chlorine and MPS?
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MPS after each use, couple of tablespoons of chlorine once per week. Maybe twice per week on the chlorine if the spa gets heavy usage.
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When I check the chlorine level in the morning and if it is zero, but we plan to go in it in the evening would you add some chlorine for the day (1 tea spoon) and then add some more after use or would you just add it after getting out?
Also, how much do you add after it has been used. Do you add a certain amount per person?
The chlorine level should never get to zero except possibly during the latter part of your soak. If it is zero for too many hours, then bacteria can grow too much and form biofilms and your tub can go south in a hurry if, for example, the chlorine level was zero for 8 or more hours. If you add enough chlorine right after our soak such that you have around 1-2 ppm at the start of your next soak, then that will work well. You won't be using the spa during the time of the high chlorine level and it will drop in the few hours after your soak as it oxidizes bather waste. It then drops more slowly until your next soak, though unfortunately is dropping faster in your case due to the ozonator which also reacts with chlorine. It would be better to have your ozonator running more right after the soak when there is more bather waste and to not have it run as often during the non-soak days so as to not use up the chlorine so quickly, but I don't think you have much control over that.
I already gave you the amounts you would use if you had no ozonator. Every person-hour in a hot (104ºF) spa requires roughly 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS). This is just a rough guide, but with an ozonator that was running right after your soak you should need less than these amounts BUT you would then need to add more in between soaks if the ozonator was still on since it will react with chlorine. This is why people are saying that you might be better off with Nature2 using mostly MPS since the ozone will not react with it so it should last longer. Also, the silver ions in Nature2 react with the most irritating component of MPS so make it more tolerable compared to using MPS without any silver ions. And as was just noted by Water Boy, you normally use MPS after each use with Nature2 and the chlorine as needed which usually means once a week though depends on bather load (chlorine is only needed because it can oxidize some things better than MPS).
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When I check the chlorine level in the morning and if it is zero, but we plan to go in it in the evening would you add some chlorine for the day (1 tea spoon) and then add some more after use or would you just add it after getting out?
Also, how much do you add after it has been used. Do you add a certain amount per person?
The chlorine level should never get to zero except possibly during the latter part of your soak. If it is zero for too many hours, then bacteria can grow too much and form biofilms and your tub can go south in a hurry if, for example, the chlorine level was zero for 8 or more hours. If you add enough chlorine right after our soak such that you have around 1-2 ppm at the start of your next soak, then that will work well. You won't be using the spa during the time of the high chlorine level and it will drop in the few hours after your soak as it oxidizes bather waste. It then drops more slowly until your next soak, though unfortunately is dropping faster in your case due to the ozonator which also reacts with chlorine. It would be better to have your ozonator running more right after the soak when there is more bather waste and to not have it run as often during the non-soak days so as to not use up the chlorine so quickly, but I don't think you have much control over that.
I already gave you the amounts you would use if you had no ozonator. Every person-hour in a hot (104ºF) spa requires roughly 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS). This is just a rough guide, but with an ozonator that was running right after your soak you should need less than these amounts BUT you would then need to add more in between soaks if the ozonator was still on since it will react with chlorine. This is why people are saying that you might be better off with Nature2 using mostly MPS since the ozone will not react with it so it should last longer. Also, the silver ions in Nature2 react with the most irritating component of MPS so make it more tolerable compared to using MPS without any silver ions. And as was just noted by Water Boy, you normally use MPS after each use with Nature2 and the chlorine as needed which usually means once a week though depends on bather load (chlorine is only needed because it can oxidize some things better than MPS).
Let me be clear on what you are saying. If three of us spend an hour in the hot tub, then it will consume 10 and a half tea spoons of dichlor??? Surely that is as much as most use in a week.
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Okay guys,
If I was to order a Nature2 cartridge, I have figured out that it would fit inside my filter by putting it in from underneath before screwing it onto the tub.
I let the chlorine level disappear to nothing.
I then use the hot tub, and when I get out I throw in some MPS ( I currently use Jacuzzi Oxidiser Non Chlorine shock - Pentapotassium Bis(Peroxymonosulpahate) Bis(Sulphate)) Is that the same stuff? and how much do you put in after a soak. Chem Geek is saying 7 teaspoons per person per user hour. So three persons spend one hour in the tub would be 21 teaspoons... thats a lot! Do they do it in barrels.
Once a week put in two tablespoons of dichlor or more often if heavily used.
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999, Here is a copy of the Nature 2 cartridge owners manual. I think this will really help if you read it briefly. You might get confused because they offer two diffrent ways to treat the water. One where you do MPS after each use and chlorine once per week. The other where you do chlorine after each use and MPS once per week. I always felt that the second method kinda defeated the purpose of using the Nature 2. If you are using chloring daily, why even bother with the Nature 2? I know there are others on here that disagree with me on that, and Im sure the daily chlorine method works good too.But, most peoples reason for wanting to use the Nature 2 is to use less chlorine, so that is why I recommend the first method.
To answer your question on the Jacuzzi brand MPS, yes that is exactly it and it would work. All you would need other than that is Chlorine and the Nature 2, and of course your pH and Alkalinity buffers.
Here is a link to the owners manual. I hope this helps:
http://www.nature2.com/files/TL2700_Nature2_Spa_Owners_Manual.pdf (http://www.nature2.com/files/TL2700_Nature2_Spa_Owners_Manual.pdf)
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Water Boy,
That is exactly what I was after, thanks.
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Let me be clear on what you are saying. If three of us spend an hour in the hot tub, then it will consume 10 and a half tea spoons of dichlor??? Surely that is as much as most use in a week.
You can't spend one hour in a 104ºF tub, at least not being in the tub the entire time. If you are in a 104ºF tub for more than 20 minutes, you increase your risk of heat-related illnesses and injury including heart attack, stroke and brain damage. But if you did have 3 people soaking in a truly hot tub for a full hour, then yes without an ozonator it would take about that much oxidizer to get rid of your bather waste from your sweat and urine. If you use less than that, then you fall behind and find that you can't hold a chlorine level in the tub. This has happened over and over again with reports on other forums (mostly poolspaforum.com) and once people use the right amount of oxidizer they stop having problems with levels going to 0 and bacteria growing.
People who use the tub at high bather loads, so long soak times and/or several people in the tub, typically do not use enough oxidizer. Such high bather-loads work better with an ozonator, but ozonators are only good for chlorine spas if you use the tub regularly such as every day or two. The ozonator will cut down such oxidizer requirements by half or more. However, in between your soaks if you don't use the hot tub for days then the ozonator uses up chlorine faster (though in a bromine tub it's the opposite where the ozone produces more bromine from the bromide bank you initially create and with MPS the ozone doesn't react with it). Your high load but infrequent use pattern is better for a bromine tub that has an ozonator, but you don't like the smell, so the other alternative is an MPS-based system, but to not be irritating and to be sanitary that requires Nature2 silver ions.
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Thanks for everyone's participation in this thread. It has been interesting to hear differing advice and it is obvious that there are several different ways of skinning the same cat. As always I will certainly consider all that has been said then make a decision based on all the information from various sources.
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I am now at the end of my second week using chlorine, and my chlorine demand seems to had slowed down.
I am now putting in 2 tea spoons when we get out in the evening, and that seems to last all of the next day. If we don't use it the day after one teaspoon is sufficient.
Could it be that until the CYA builds up, the chlorine burns off too quickly and after adding around 20 tea spoons in the first week there is now some CYA that is making the chlorine it last longer. Any thoughts on this theory?
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That's possible in the first few days since there can be more chlorine outgassing faster without any CYA in the water since the active chlorine level is higher, but after a week I wouldn't expect to see much change from that. More likely is that there were things to oxidize in your water and you just got caught up. In any event, glad to hear that your chlorine demand is stabilizing. Just note that by using Dichlor-only you will at some point notice that the water won't stay in as good shape and will need more chlorine to clear (i.e. shock) due to the CYA buildup making the chlorine less effective. However, by the time that happens you might decide to change the water anyway. If you want the water to last longer...well, we've already talked about that.
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I don't think i could use the cartridge that you mention because my filter doesn't have a centre section that comes off. It is fixed.
I am encouraged to know that there doesn't have to be a constant reading of chlorine.
My ozonator is always bubbling, even with the pump on.
I could be wrong, and one of the hot tub wizards here will tell me if I am I'm sure, but the "bubbles" are created by your circ pump going through a venturi valve, at which point your hose from the Ozonator is plumbed in. This is how my tub is (I know, because I literally replaced it 2 days ago!). When I turn on the pumps the green LED on the MCD 50 goes off - you only have so much "power" to go around. If I have no heat on (as in, the tub is at 103, and doesn't need heated) and the 2 pumps are on low, it stays on. The moment the heater kicks on with the pumps the power goes off to the MCD 50.
That is why spa-kits are expensive - because they have to measure what type of electricity goes where. After a couple of years making my spa an enjoyable experience (my joke about it was that I got it from my in-laws and it was the gift that keeps on taking!) the ozonator typically does cut out. At least that's my experience.
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My hot tub has a circulation pump and one 2-speed jet pump. It is in 32 amp mode so that the heater Will work whilst everthing is on. I think my ozozator bubbles the most when the jet pump is off. It bubbles a little when it is on speed one and nothing (or possibly a little) when on speed two. So still not entirely sure if it is on whilst i am sitting in it.
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The only sure way to know is to unscrew the front panel and see what happens to the light on the CD ozonator.