Pseudomonous Rash

[LilRed]

Had my Hot tub for a week and my husband has got hot tub rash. I am using cholorine and the spa does have an ozonator. I have ordered the taylor kit to use. My question is should I empty the tub and start over? I hae shocked and cholorinated it with dichlor. I have been in it much more and do not have it. If I don't have to drain it what else can I do? Thanks so much.

[chem geek]

Though there have been four reports of rashes on this forum from hot tub users using Dichlor exclusively, they all got those after about 1.5 to 2 months of use. It is unlikely that the rash is from the bacteria Pseudomonas aeruginosa that causes hot tub itch unless the spa either did not have enough chlorine over an extended period of time or had too much CYA in it from the Dichlor, but that would take more Dichlor than the normal amount to be used in one week. For every 1 ppm Free Chlorine (FC) added by Dichlor, it also adds 0.9 ppm of Cyanuric Acid (CYA).

Can you tell me the approximate volume of your spa and how much Dichlor you added over the week, both for shocking and for regular chlorination? You can certainly drain and start over, but it would be good to know what possibly happened so that it won't happen again.

Allergies to chlorine itself are very rare -- allergic reactions to bromine are more common -- but it is certainly possible your husband has that. It is also possible that the higher actual disinfecting chlorine levels in the first few days were irritating (that is, too little CYA initially so the chlorine was too strong).

Richard

[104 Degrees]

Richard

Ive dumped my tub and will take a cya Test next tuesday. I plan on going with the Bleach this time around if the cya is at 20ppm. I'll keep you posted.

John

[chem geek]

Richard

Ive dumped my tub and will take a cya Test next tuesday. I plan on going with the Bleach this time around if the cya is at 20ppm. I'll keep you posted.

John

John,

A couple of things. I never answered the question in this post where the spa store said that the rash from high CYA (presumably she meant hot tub itch from low disinfection that can be caused by high CYA) would occur all over the body. That is simply not true. The bacteria is opportunistic and will grow in weak spots on your skin so if you've got any sort of cut or sore to begin with or a weak spot (thin or irritated area) in the skin, then that's where the rash will most likely occur. This is part of the reason why most people don't get a rash even if exposed to the bacteria. It's a combination of the bacteria plus the person's individual skin condition that can lead to a rash. The lower right side of your belly and the left side of your ankle are places where the clothing (pants/belt, socks) may irritate the skin -- but that's just a guess on my part. I know that the skin around the tops of my socks seems thinner and has the hair partially rubbed off.

Definitely let me know what happens with the "don't let CYA get above 20 ppm and keep 4 ppm FC" approach. It should take about a week of Dichlor usage to get to around 20 ppm CYA (it's after adding 22 ppm FC equivalent of Dichlor). As I've said in another post, one person reported positive results, another reported negative results (i.e. no improvement) and the other two never reported back. So it's pretty darn inconclusive right now and I'm probably being overly conservative about this. The bottom line is finding a solution that makes your spa experience better.

Richard

[104 Degrees]

said that the rash from high CYA (presumably she meant hot tub itch from low disinfection that can be caused by high CYA) would occur all over the body. That is simply not true. The bacteria is opportunistic and will grow in weak spots on your skin so if you've got any sort of cut or sore to begin with or a weak spot (thin or irritated area) in the skin, then that's where the rash will most likely occur. This is part of the reason why most people don't get a rash even if exposed to the bacteria. It's a combination of the bacteria plus the person's individual skin condition that can lead to a rash. The lower right side of your belly and the left side of your ankle are places where the clothing (pants/belt, socks) may irritate the skin -- but that's just a guess on my part. I know that the skin around the tops of my socks seems thinner and has the hair partially rubbed off.

Definitely let me know what happens with the "don't let CYA get above 20 ppm and keep 4 ppm FC" approach. It should take about a week of Dichlor usage to get to around 20 ppm CYA (it's after adding 22 ppm FC equivalent of Dichlor). As I've said in another post, one person reported positive results, another reported negative results (i.e. no improvement) and the other two never reported back. So it's pretty darn inconclusive right now and I'm probably being overly conservative about this. The bottom line is finding a solution that makes your spa experience better.

Richard

I'm going to have it tested two months after to see if the cya went up and no more rash.

Thanks bud

[LilRed]

Though there have been four reports of rashes on this forum from hot tub users using Dichlor exclusively, they all got those after about 1.5 to 2 months of use. It is unlikely that the rash is from the bacteria Pseudomonas aeruginosa that causes hot tub itch unless the spa either did not have enough chlorine over an extended period of time or had too much CYA in it from the Dichlor, but that would take more Dichlor than the normal amount to be used in one week. For every 1 ppm Free Chlorine (FC) added by Dichlor, it also adds 0.9 ppm of Cyanuric Acid (CYA).

Can you tell me the approximate volume of your spa and how much Dichlor you added over the week, both for shocking and for regular chlorination? You can certainly drain and start over, but it would be good to know what possibly happened so that it won't happen again.

Allergies to chlorine itself are very rare -- allergic reactions to bromine are more common -- but it is certainly possible your husband has that. It is also possible that the higher actual disinfecting chlorine levels in the first few days were irritating (that is, too little CYA initially so the chlorine was too strong).

Richard

It sure looks like Pseudomonas to me. (I'm a Critical Care RN and have looked at pictures in the dermatology books..papular nodules with pustules over trunk and arms) I have seen it before. And yes I thought it was so unusal that my husband would get it so soon. We added chemicals to the spa on start up. Every time I checked the water the cholorine was non-existant according to the test strips. I believe I have added dichlor about a tablespoon about 6-7 times. The spa is 200 gallons. The tub sat over the weekend Fri Sat and Sun since we work 12hr weekend shifts. When I checked it Monday...zero cholorine in it. So I guess things could have grown over the weekend since I didn't check it until Monday. I have been in the tub aobut 2-3 times a day on my days off. (I rode bike here in the mountains and boy it sure feels good after exercising). I have shocked it with Spa guard once prior to today. I have ordered the Taylor kit and am waiting for it to come. I don't think it is an allergy since we have been in lots of pools and hot tubs on vacation and my husband has never reacted to cholorine before. I have been searching for another reason for it and can't find any. I am a novice at this and sure appreciate any input you would have.

We have tried to be careful..showering before getting in and after getting out. I think I need to check it more often. When they set it up they said just check it once a week and don't obcess over it. I jsut don't want the bug to colonize in the tub and have troulbe getting rid of it. Thanks for the input. Jeanie

[104 Degrees]

It sure looks like Pseudomonas to me. (I'm a Critical Care RN and have looked at pictures in the dermatology books..papular nodules with pustules over trunk and arms) I have seen it before.

Jennie

My rash dosent look like what you are saying. its more like red spots that itch. its only on my left ankle and my right stomac belt line? thats the only place it grows.

John

[LilRed]

It sure looks like Pseudomonas to me. (I'm a Critical Care RN and have looked at pictures in the dermatology books..papular nodules with pustules over trunk and arms) I have seen it before.

Jennie

My rash dosent look like what you are saying. its more like red spots that itch. its only on my left ankle and my right stomac belt line? thats the only place it grows.

John

I have seen psuedomonas before. It is red raised and some may develope small pustules. I have a picture of Psuedomonas folliculitis but I don't know how to inset it here. I can e-mail it to you. How big are your spots? this can occur anywhere. It is a infection of the hair follicule. I jsut don't want it to re-occur due to improper sanitization. I also think my ph is high. It is on the high end of the tet strip. i am looking for my Taylor kit to come in the mail soon.

[104 Degrees]

place it grows.

John

I have seen psuedomonas before. It is red raised and some may develope small pustules. I have a picture of Psuedomonas folliculitis but I don't know how to inset it here. I can e-mail it to you. How big are your spots? this can occur anywhere. It is a infection of the hair follicule. I jsut don't want it to re-occur due to improper sanitization. I also think my ph is high. It is on the high end of the tet strip. i am looking for my Taylor kit to come in the mail soon.

I dont know how to post a pic at this time or i will tell you. There is a way and i will find it.

I dont have the rash now(its summer) and i hope i dont again . if what i do does not work i'll try and post a pic of it.

John

[chem geek]

One tablespoon of Dichlor is probably around one-half of an ounce weight which would raise the FC by 10.4 ppm and the CYA by 9.4 ppm in 200 gallons. 6-7 times would bring the CYA up to around 60 ppm which is on the higher side, but not extraordinary (though I recommend keeping the CYA at around 20 ppm). What is very surprising is that the 10 ppm FC gets used up so quickly -- you said it measured nothing on the test strips each time. Of course, if the test strips are DPD types of tests, they could bleach out at around 10 ppm or higher.

Going an entire weekend without chlorine could certainly allow for the bacteria to grow IF it got into the tub at some point when the chlorine was low.

I would do the following things. First, get a good test kit such as the Taylor K-2006 or at least a standalone FAS-DPD test kit so you can measure the chlorine more accurately. Second, you can start over with a fresh refill of water and then add two tablespoons of Dichlor to shock it with chlorine and get to around 20 ppm FC and 18 ppm CYA. Thereafter, you can use 2 fluid ounces (4 tablespoons) of 6% unscented Clorox Regular bleach (or off-brand Ultra bleach) as your chlorine source to get to around 5 ppm FC (I recommend around 4 ppm FC, but 5 is close enough and results from 4 tablespoons). You will probably need to add chlorine every day, especially if you use the tub most days, but if the tub is covered and the jets are not on (just slow circulation) and you don't use the tub every day, then the chlorine should last longer. After about a month, you can test the CYA to see if it still registers and if it's not at around 20 ppm you can add Dichlor to get the CYA back up. If you skip a day adding chlorine (such as that long weekend), be sure to add the chlorine before you use the tub, preferably an hour or more before to not only kill the bacteria but to reduce the smell of the chlorine (keeping the top off). Make sure that at least some chlorine is registered when you enter the tub and you can add more chlorine when you get out.

Richard

[LilRed]

One tablespoon of Dichlor is probably around one-half of an ounce weight which would raise the FC by 10.4 ppm and the CYA by 9.4 ppm in 200 gallons. 6-7 times would bring the CYA up to around 60 ppm which is on the higher side, but not extraordinary (though I recommend keeping the CYA at around 20 ppm). What is very surprising is that the 10 ppm FC gets used up so quickly -- you said it measured nothing on the test strips each time. Of course, if the test strips are DPD types of tests, they could bleach out at around 10 ppm or higher.

Going an entire weekend without chlorine could certainly allow for the bacteria to grow IF it got into the tub at some point when the chlorine was low.

I would do the following things. First, get a good test kit such as the Taylor K-2006 or at least a standalone FAS-DPD test kit so you can measure the chlorine more accurately. Second, you can start over with a fresh refill of water and then add two tablespoons of Dichlor to shock it with chlorine and get to around 20 ppm FC and 18 ppm CYA. Thereafter, you can use 2 fluid ounces (4 tablespoons) of 6% unscented Clorox Regular bleach (or off-brand Ultra bleach) as your chlorine source to get to around 5 ppm FC (I recommend around 4 ppm FC, but 5 is close enough and results from 4 tablespoons). You will probably need to add chlorine every day, especially if you use the tub most days, but if the tub is covered and the jets are not on (just slow circulation) and you don't use the tub every day, then the chlorine should last longer. After about a month, you can test the CYA to see if it still registers and if it's not at around 20 ppm you can add Dichlor to get the CYA back up. If you skip a day adding chlorine (such as that long weekend), be sure to add the chlorine before you use the tub, preferably an hour or more before to not only kill the bacteria but to reduce the smell of the chlorine (keeping the top off). Make sure that at least some chlorine is registered when you enter the tub and you can add more chlorine when you get out.

Richard

You have been such a help as I am learning the hot tub chemistry. Yesterday I shocked it with a non cholorine shock and added dichlor. The strip read the darkest purple. I then got in it later in the evening when the cholorine was down. I was in it 15 minutes. This am I am barely registering cholorine on my strip. So the tub or me uses up the cholorine. My bigest question..should I empty the tub? You said "I could" but do I need to? Also, how does the CYA come down? Does shocking lower it or does it just dissapate over time? And another clarification, should I add the entire 4 tablespoons of bleach each time I need to add cholorine? And do I need to still do the non cholorine shock also? My ph on the stip is on the uppper end of high. I will know more whenI get my Taylor test kit I have on order. How should I lower that? Lots of questions and you have been such a big help. Jeanie

[chem geek]

You are right that either something in the tub water or you are using up the chlorine. 200 gallons for one person is pretty small so a lot of the chlorine may be getting used up from you. Remember that "ppm" is a concentration so 4 ppm in 200 gallons is half the total amount of chlorine as 4 ppm in 400 gallons. A lot also dissipates into the air from outgassing due to the hot water temperature and the aeration from the jets. You can easily determine (if it matters to you) how much you contribute to the chlorine usage by opening up and running your tub jets without getting into it. It doesn't really matter, though, unless you are curious as to the source of the usage. Do you cover your tub when not in use? Is it indoor or outdoor and if outdoor is it exposed to sunlight (if uncovered)? Covering the tub when not in use will help a lot.

CYA normally only goes down via dilution, but it is possible to get broken down by very high levels of chlorine at higher pH though that is a slow process. I doubt that your CYA level has changed much so that's why I suggested you replace the water so that you can get down to around 20 ppm CYA. It's up to you, but since you've got an itch problem, then if you want to be most conservative then I would replace your water and try what I said -- replace the water, add 2 tablespoons of Dichlor (mostly to shock it, but also to add CYA to the water), then thereafter add 4 tablespoons of bleach, probably every day. Yes, you add it all at one time since it only increases the FC to 5 ppm.

As for the non-chlorine shock (which I assume is potassium monopersulfate -- you can check the ingredients on the bottle), in theory it should help reduce chlorine usage by oxidizing organics before chlorine does, but clearly in your case it doesn't seem to be helping that much for whatever reason. The non-chlorine shock is also acidic which should help keep the pH down a bit (more on that later).

The higher pH makes the chlorine somewhat less effective (not as much as it would if you didn't have CYA in the water) and the pH goes up because the water in the tub is intentionally over-carbonated (that's what TA mostly measures). Having the TA be lower helps reduce this problem so if you are starting up with a fresh refill of water, do not add any Alkalinity Up sort of product. Your tap water probably has more than enough TA already -- you can measure it to see what it is. If it's at least 50 ppm, it's plenty. If it's higher than 80, then that will contribute to the pH rise. If you keep your tub covered when not in use, that will help keep the pH more stable. It is the outgassing of carbon dioxide from the water that causes the pH to rise. Using the jets makes aeration that has this outgassing go faster -- just like blowing bubbles in a carbonated beverage to make it go flat.

As for lowering the pH, you add acid. With the small amounts of acid you will need to add, you would use dry acid (sodium bisulfate) often sold as "Spa Down". You'll probably add about 0.4 ounces weight which is around 0.25 fluid ounces of half a tablespoon (one and a half teaspoons). You can then remeasure the pH after about 15 minutes with circulation (not aeration) of the tub water. Then add more acid if needed to get closer to 7.5 in pH.

Richard

[dave nh]

This is an intersting thread, i can confirm in my case that Richards information is on the money. My Cyn levels have risen rapidly in the last couple weeks and is now over 100ppm. The tub is new (425 gal) so it has been getting alot of use. Have been using the dealer supplied chemicals, dichlor as well as a dichlor based spa shock packets (spa guard). . I have an ozonator and it runs 24/7, richard is this enough to control the "swimmers itch"? I try and keep my free chlorine at 1-3 ppm.

It looks like i have added about 16oz of dichlor so far plus shocked it with the spa shock packets around four times.

I have not noticed a significant water quality change, although the ph has been drifting lower and is now on the low side 7.3/2.

Based on some of the posts i am going to try a combination of dichlor/ mps shock / and bleach the next go around.

Richard, any startup advice for this volume would be appreciated and what to look for. My fill water is from a well and is around ph 7.8 and very alkaline 180 ppm. Also, how long can i wait to shock with dichlor initially? I might need to bring my ph and alk down and give the stain and scale a chance to work so i dont turn my water yellow and get ring stains around from the tub ( i have a little dissolved iron in the water). Thanks!

[chem geek]

First of all, I don't want anyone to jump to any conclusions that there is anything wrong with the Vermont method of using only Dichlor for sanitation. There is no question that it will increase the CYA level over time -- that is a chemical fact. The question is whether it rises enough to prevent chlorine from killing the bacteria that causes hot tub itch. That is still an open question. I found ONE source that gave me a CT (chlorine concentration times time) value for the bacteria that causes hot tub itch and I computed a reasonable FC and CYA combo that should work against that bacteria given that number. I may be way too conservative about this. There is no question that the high CYA level would be an issue for developing algae, but that isn't normally a problem in a hot tub due to the high temperatures and lack of sunlight (since they are generally covered) -- a pool is another matter entirely. Most bacteria are much, much easier to kill than algae -- the hot tub itch bacteria appears to be an exception.

As for the ozonator, it probably kills bacteria passing through the ozonator very effectively, but I cannot find specific CT values for ozone against the hot tub itch bacteria to be more certain. Remember, however, that the ozone does not stay as a residual in the water so though free-floating bacteria getting circulated through the ozonator may get killed, any stuck to biofilms on hot tub surfaces won't get killed by the ozonator. This is why an EPA approved sanitizer (chlorine, bromine, biguanide) is always required since these are the only ones that retain a residual (easily -- chlorine dioxide is also effective, but very sensitive to breakdown from sunlight and may be "too" strong an oxidizer to be exposed to). Also, in larger bodies of water (i.e. pools), the time for one turnover is hours and far longer than the time it would take some fecal matter to reach one's mouth or nose so that's why a sanitizer residual is required -- to kill 99% of such bacteria in a minute or less.

The use of Dichlor is actually acidic since the usage of chlorine is acidic. So when you switch to bleach, you may notice that the pH will tend to rise instead of fall. You can lower the TA level (down to 50, if necessary) to help reduce that problem. Also, non-chlorine shock (MPS) also slightly reduces the pH. The use of bleach as a chlorine source is actually pH neutral (when accounting for both chlorine addition and usage), but the pH rise is due to carbon dioxide outgassing.

With your very alkaline well water, your use of bleach will be frustrating since you'll find a strong tendency for the pH to rise. Your use of Dichlor has hidden that problem. If you lower the TA, then there will be less of a tendency for the pH to rise. You can lower your TA after a fresh fill by lower the pH with dry acid down to 7.0 and then aerate using your spa jets. That makes the pH rise at which point you add more dry acid to lower it back to 7.0. Keep doing this until the TA drops to at least 80. You then just run the jets without adding any acid to get to the pH you want -- probably around 7.5. You essentially are driving carbon dioxide out of the water just like blowing bubbles in a carbonated beverage makes it go flat. With the lower TA, you should find less of a tendency for the pH to rise as quickly, though it probably still will somewhat.

Yes, you can adjust your fresh water after a refill first to have the metal sequestrant hold the iron and then adjust the pH and TA as described above. After you are done with that, then add Dichlor to both shock and to add CYA to the water. If you add the amount of Dichlor that would give you 22 ppm FC, then that's also 20 ppm CYA and is a good starting amount. When the FC drops down below 10 -- probably by the next day -- you are ready to use your tub and will thereafter just add bleach (probably every day, depending on tub usage) to get the FC to 4 ppm which with 20 ppm CYA should be enough to kill hot tub itch bacteria even if they are stuck to hot tub surfaces (i.e. even if they don't make it through the ozonator).

Note that the ozonator is a mixed blessing. It should help oxidize organics so technically you shouldn't need to use MPS shock. In theory, your chlorine usage should go down since the chlorine won't need to oxidize organics, but the ozone itself can oxidize chlorine so use of the ozonator might actually deplete your chlorine faster than not using it. That's something you can experiment with to see what works best in your situation.

Richard

[LilRed]

You are right that either something in the tub water or you are using up the chlorine. 200 gallons for one person is pretty small so a lot of the chlorine may be getting used up from you. Remember that "ppm" is a concentration so 4 ppm in 200 gallons is half the total amount of chlorine as 4 ppm in 400 gallons. A lot also dissipates into the air from outgassing due to the hot water temperature and the aeration from the jets. You can easily determine (if it matters to you) how much you contribute to the chlorine usage by opening up and running your tub jets without getting into it. It doesn't really matter, though, unless you are curious as to the source of the usage. Do you cover your tub when not in use? Is it indoor or outdoor and if outdoor is it exposed to sunlight (if uncovered)? Covering the tub when not in use will help a lot.

CYA normally only goes down via dilution, but it is possible to get broken down by very high levels of chlorine at higher pH though that is a slow process. I doubt that your CYA level has changed much so that's why I suggested you replace the water so that you can get down to around 20 ppm CYA. It's up to you, but since you've got an itch problem, then if you want to be most conservative then I would replace your water and try what I said -- replace the water, add 2 tablespoons of Dichlor (mostly to shock it, but also to add CYA to the water), then thereafter add 4 tablespoons of bleach, probably every day. Yes, you add it all at one time since it only increases the FC to 5 ppm.

As for the non-chlorine shock (which I assume is potassium monopersulfate -- you can check the ingredients on the bottle), in theory it should help reduce chlorine usage by oxidizing organics before chlorine does, but clearly in your case it doesn't seem to be helping that much for whatever reason. The non-chlorine shock is also acidic which should help keep the pH down a bit (more on that later).

The higher pH makes the chlorine somewhat less effective (not as much as it would if you didn't have CYA in the water) and the pH goes up because the water in the tub is intentionally over-carbonated (that's what TA mostly measures). Having the TA be lower helps reduce this problem so if you are starting up with a fresh refill of water, do not add any Alkalinity Up sort of product. Your tap water probably has more than enough TA already -- you can measure it to see what it is. If it's at least 50 ppm, it's plenty. If it's higher than 80, then that will contribute to the pH rise. If you keep your tub covered when not in use, that will help keep the pH more stable. It is the outgassing of carbon dioxide from the water that causes the pH to rise. Using the jets makes aeration that has this outgassing go faster -- just like blowing bubbles in a carbonated beverage to make it go flat.

As for lowering the pH, you add acid. With the small amounts of acid you will need to add, you would use dry acid (sodium bisulfate) often sold as "Spa Down". You'll probably add about 0.4 ounces weight which is around 0.25 fluid ounces of half a tablespoon (one and a half teaspoons). You can then remeasure the pH after about 15 minutes with circulation (not aeration) of the tub water. Then add more acid if needed to get closer to 7.5 in pH.

Richard

Thanks so much Richard. I also have water from a well. I will dump it on Monday and start over. Also, since the water is 56 degrees coming out of the well should I add the chemicals into the cold water or into the water when it is warmer? I also have the problem with a higher ph. I will know the exacts when I get my taylor kit. I do keep the cover on it and it is an outside tub. Doesn't get much sun if I sit in it in the daylight.

My hubby is now on antibiotics for the rash..man did it explode. Did some research and found that 15% of the population have pseudomonas as a flora on skin. Opening up the pores with strong jets flowing and poor cholorine levels probably contributed. So far, I have no rash and I love the tub. Will let you know how it goes after I get the tub back up and my husbands rash is gone. The tub is a no-no for anyone with an active skin rash. I so appreciate your expertise!!

[dave nh]

Kelly,

On your initial fill of your new tub, did you fill it twice? Chlorinating then draining the initial fill right away then filling again? I was just wondering if you had some bad water in the line from factory testing, etc. that ate up all your FC and perhaps led to the rash.

[chem geek]

Also, since the water is 56 degrees coming out of the well should I add the chemicals into the cold water or into the water when it is warmer?

The bacteria reproduce much more slowly in the colder water, but chlorine kills them more slowly as well. Generally, higher temps are more efficient at killing bacteria faster than they reproduce (i.e. the "CT" values are lower at higher temperatures), but you really don't want the bacteria there or taking hold at any time so I would add the chemicals to the cold water, then retest when warmed up and adjust as needed.

[LilRed]

Also, since the water is 56 degrees coming out of the well should I add the chemicals into the cold water or into the water when it is warmer?

The bacteria reproduce much more slowly in the colder water, but chlorine kills them more slowly as well. Generally, higher temps are more efficient at killing bacteria faster than they reproduce (i.e. the "CT" values are lower at higher temperatures), but you really don't want the bacteria there or taking hold at any time so I would add the chemicals to the cold water, then retest when warmed up and adjust as needed.

This weekend I checked the tub everynight when I came home. I had to add bleach every single time. And I didn't use it. The tub must justuse it up. I never refilled the tub twice on start up. Hopefully we wont have this problem again. And thanks to chem geek I understand water chemistry so much better. Jeanie

[chem geek]

This weekend I checked the tub everynight when I came home. I had to add bleach every single time. And I didn't use it. The tub must justuse it up. I never refilled the tub twice on start up. Hopefully we wont have this problem again. And thanks to chem geek I understand water chemistry so much better. Jeanie

Jeanie,

You might try turning off your ozonator and seeing if the chlorine continues to dissipate as quickly when you aren't using the tub. Ozone is a stronger oxidizer than chlorine so can oxidize chlorine to form chlorate (via chlorite). Chlorine will generally dissipate in a hot tub in one day if the tub is used, aerating jets are on, etc., but if covered and not in use it usually lasts a little longer though not by much (i.e. perhaps 2 or 3 days) depending on temperature. The hot tub volume is low so the chlorine is very easily overwhelmed by organics in the water which is part of the reason to use a regular non-chlorine shock (though in theory with your ozonator you wouldn't have to do that -- but the ozonator itself may reduce the chlorine).

So if you turn off your ozonator, let us know if that helps keep the chlorine level up longer. You'll then be in a conundrum of what to do -- use the ozonator to help breakdown organics and kill bacteria, but also use up chlorine and have to add it every day vs. not use the ozonator to keep the chlorine level up, but have to use a non-chlorine shock (potassium monopersulfate) to help oxidize organics. First, see what happens with the ozonator off, and then we can deal with what to do next.

Richard

[104 Degrees]

Richard

My tub tested to low on the color reader for cya. Its been a week since i filled it and i have used about a teaspoon of dichlor a day. we are going to test it next tuesday. Everything else tested fine. its going to start getting colder so it will get used more.

John

[LilRed]

This weekend I checked the tub everynight when I came home. I had to add bleach every single time. And I didn't use it. The tub must justuse it up. I never refilled the tub twice on start up. Hopefully we wont have this problem again. And thanks to chem geek I understand water chemistry so much better. Jeanie

Jeanie,

You might try turning off your ozonator and seeing if the chlorine continues to dissipate as quickly when you aren't using the tub. Ozone is a stronger oxidizer than chlorine so can oxidize chlorine to form chlorate (via chlorite). Chlorine will generally dissipate in a hot tub in one day if the tub is used, aerating jets are on, etc., but if covered and not in use it usually lasts a little longer though not by much (i.e. perhaps 2 or 3 days) depending on temperature. The hot tub volume is low so the chlorine is very easily overwhelmed by organics in the water which is part of the reason to use a regular non-chlorine shock (though in theory with your ozonator you wouldn't have to do that -- but the ozonator itself may reduce the chlorine).

So if you turn off your ozonator, let us know if that helps keep the chlorine level up longer. You'll then be in a conundrum of what to do -- use the ozonator to help breakdown organics and kill bacteria, but also use up chlorine and have to add it every day vs. not use the ozonator to keep the chlorine level up, but have to use a non-chlorine shock (potassium monopersulfate) to help oxidize organics. First, see what happens with the ozonator off, and then we can deal with what to do next.

Richard

Richard,

I will need dto check and see if I can turn the ozonator off. I don't know if I can. the water has been crystal clear and I have just been adding bleach daily and the cholorine is up. I haven't gotten my taylor kit yet. I am gettingin a routine and I love soaking in it. Thanks for all your help. Jeanie

[raydz]

I don't want to change the topic of this thread.... but introduce another possibility for your rash. Last year..... I developed a similar rash which nurses and doctors thought was "Hot Tub Itch". They put me on a number of strong medications....... but it kept coming back. After visiting a dermatologist several times they found the culprit MPS! After emptying the tub and re-filling.... I know just use di-chlor to get the stabilizer levels up to 20.... then just use bleach after each use..... along with a ozonator.... I have not had the slightest rash in the last 9 months.... I have read around the internet that There are people allergic to MPS ..... especially men. Good luck in finding the sourse of your rash.... I am certainly glad I found mine..... because I love the hot tub.

[104 Degrees]

because I love the hot tub.

I do too Is MPS Non Chlorine shock??

John

[chem geek]

Yes, MPS is Potassium monopersulfate and is non-chlorine shock, but you should be able to check the ingredients for monopersulfate. That's very interesting that some are allergic to it. Except for being an oxidizer, it's relatively benign. I wonder if it's the oxidizer part, persulfate (SO5), that's the issue or the sulfate (SO4). If the rash comes up soon after using the non-chlorine shock (rather than at the end of the week after the shock should be fully dissipated), then it's the oxidizer part that is the problem. If the rash comes up only after continued use over many weeks or months and doesn't flare up only soon after addition of MPS, then it may be the sulfates since those just build up over time.

[104 Degrees]

Yes, MPS is Potassium monopersulfate and is non-chlorine shock, but you should be able to check the ingredients for monopersulfate. That's very interesting that some are allergic to it. Except for being an oxidizer, it's relatively benign. I wonder if it's the oxidizer part, persulfate (SO5), that's the issue or the sulfate (SO4). If the rash comes up soon after using the non-chlorine shock (rather than at the end of the week after the shock should be fully dissipated), then it's the oxidizer part that is the problem. If the rash comes up only after continued use over many weeks or months and doesn't flare up only soon after addition of MPS, then it may be the sulfates since those just build up over time.

This could be it for me.I'm going to test again this tuesday. I'll le you know. Ive only put one tablespoon in so far.

John