Hot Tub Rash

[IlliniFan]

I have a one month old J335. I have been using reserve and renew by leisure time which is a bromide based system. I have been following instructions given and shocking with MPS after every soak. I now have lovely spots on my torso. Don't itch, not pustules. The question is, do I need to drain spa? Dealer says no. What do you think? I did put in bromine tabs. I want to know I have bromine in spa now. With reserve and renew, after adding renew, bromine level goes way up and then pretty much disappates. To drain or not to drain. That is the question.

[waterbear]

I have a one month old J335. I have been using reserve and renew by leisure time which is a bromide based system. I have been following instructions given and shocking with MPS after every soak. I now have lovely spots on my torso. Don't itch, not pustules. The question is, do I need to drain spa? Dealer says no. What do you think? I did put in bromine tabs. I want to know I have bromine in spa now. With reserve and renew, after adding renew, bromine level goes way up and then pretty much disappates. To drain or not to drain. That is the question.

Reserve and Renew are a two step bromine system, sodium bromide and oxidizer. Adding tabs makes it a three step bromine system and makes the bromine levels easier to maintain. Otherwise you tend to see the level shoot up when you oxidize and then drop quickly. the downside to two step systems.

[biggz]

I have a one month old J335. I have been using reserve and renew by leisure time which is a bromide based system. I have been following instructions given and shocking with MPS after every soak. I now have lovely spots on my torso. Don't itch, not pustules. The question is, do I need to drain spa? Dealer says no. What do you think? I did put in bromine tabs. I want to know I have bromine in spa now. With reserve and renew, after adding renew, bromine level goes way up and then pretty much disappates. To drain or not to drain. That is the question.

'IlliniFan', Have you considered using a chlorine system, instead of bromine. When I opened my tub I used the same system and quickly realized it was not for me. Many people don't like the "smell" of chlorine, but I personally think bromine smells much worse, and if you are a daily soaker chlorine is very efficient.

[TinyBubbles]

I think it's the MPS. I only use MPS once every week or two and get those bumps every time. I am going to shock with dichlor weekly from now on and continue adding dichlor after each soak.

[chem geek]

Some people are sensitive to MPS. Instead of using Dichlor for shocking, use bleach instead. Otherwise you'll build up the Cyanuric Acid (CYA) level in the spa very quickly. Even using Dichlor after every soak will build up the CYA level. If you use Dichlor initially for the first week or two after a refill and then switch to bleach, you won't build up the CYA above 20 ppm or so. For every 1 ppm FC added by Dichlor it also adds 0.9 ppm to CYA.

Richard

[TinyBubbles]

I just can't bring myself to use bleach. I have an ozonator and an N2 cartridge, so I'm not going to shock very often. We all have our limitations and me around liquid bleach is a NO NO! Chem geek, does anything get rid of CYA other than a water change?

[chem geek]

I just can't bring myself to use bleach. I have an ozonator and an N2 cartridge, so I'm not going to shock very often. We all have our limitations and me around liquid bleach is a NO NO! Chem geek, does anything get rid of CYA other than a water change?

Unfortunately not. Extremely high levels of chlorine at high pH (9-10) can breakdown CYA, but that's an FC level higher than the CYA level (in ppm). There is a CYA remover product on the market, but it's a polymer that makes a mess when it consolidates with CYA. Adding melamine would precipitate CYA (just like the CYA measuring test in test kits), but would turn the water cloudy and then require a flocculant. So there's no good way to reduce CYA other than dilution.

There are some soil bacteria that breakdown CYA and sometimes if you let a pool go over the winter and don't maintain it with chlorine then the CYA will be seen to go away. The breakdown product is ammonia, however, so it takes a lot of chlorine during spring startup to get rid of the ammonia.

Just keep in mind that in the water, the Dichlor and the bleach produce identical chlorine. The only difference is that the Dichor adds to CYA while the bleach does not and the Dichlor is initially more pH neutral than the bleach. I understand you may not like the fumes from bleach when adding it. If it's a real problem for you, just use the Dichlor and live with it. It's better to have the tub mostly sanitized than not and the ozone may help kill off any floating hot tub itch bacteria.

The off-brand regular unscented bleach is usually not as strong -- perhaps 3% instead of 6% -- so might not smell as much when you add it, if that's the main problem for you. Another alternative you might consider is using Lithium Hypochlorite since that is a powder and doesn't add CYA. It's essentially the same as bleach, but it's far more expensive (about 7 times as expensive as bleach, though only 3-4 times expensive as Dichlor), but for the small quantities added to a spa, that might not be too bad.

Richard

[TinyBubbles]

I must admit that I haven't tested for cya levels. I will do so and then see if I HAVE to rethink my bleach opinion. Why do hot tub mfg's void the warranty if you use liquid bleach? Can the even tell if you've used liquid bleach?

[chem geek]

I must admit that I haven't tested for cya levels. I will do so and then see if I HAVE to rethink my bleach opinion. Why do hot tub mfg's void the warranty if you use liquid bleach? Can the even tell if you've used liquid bleach?

I wanted to give you yet another option which is Cal-Hypo. That will increase Calcium Hardness (CH), but unless you have really hard water to start with (such as well water), then you aren't likely to increase CH by too much. For every 1 ppm FC added by Cal-Hypo, it adds 0.7 ppm to CH. You do need to pre-dissolve the Cal-Hypo in a bucket of spa water before adding it into the spa as it does not dissolve readily (unlike Dichlor and Lithium Hypochlorite). So even adding 4 ppm FC per day every day for 90 days, that increases CH by 252 ppm so if you are starting with less than 100 ppm CH and you keep your TA level low (80 or lower), then that can work out OK, but you'd have to change the water after 90 days or else the ever-higher CH would eventually lead to scaling.

The main reason for not allowing bleach or technically any non-stabilized source of chlorine is that if you only used such sources of chlorine right after a refill than you would be overdosing with chlorine and that would degrade the cover more quickly (and wouldn't be good on your swimsuits, skin or hair, either). It's not just a little overdosing either, but a factor of 20 or more because having 20 ppm CYA in the water literally reduces disinfecting chlorine (hypochlorous acid) concentration by about a factor of 20 (at a pH near 7.5). The other possible reason, specifically with bleach, is that being a liquid it may be more likely to splash onto the cover in concentrated form though that sounds like a stretch to me. The last reason is that adding bleach quickly without the pump circulating can result in the bleach settling to the bottom of the spa (since it is denser than water until it fully dilutes/dissolves) where it will be corrosive if not diluted. Adding it slowly over a return/jet flow eliminates that problem.

Again, you do want some CYA in the water or else the disinfecting chlorine level will be too high. So you do want to use Dichlor for a short time. But then switching to bleach or Lithium Hypochlorite or Cal-Hypo will prevent the CYA from continuing to climb.

I also want to refer you to this post where Shaamus lists the order for degradation of spa covers and not that surprisingly it pretty much lines up with the amount of disinfecting chlorine. Using Dichlor and then switching to an unstabilized source of chlorine would probably be the next item at the bottom of the list though probably not that much different than the 5/6 categories and it possibly might be better than 5/6 if the Dichlor only approach got the CYA so high as to really slow down the breakdown of monochloramine. If you used only unstabilized chlorine (such as bleach) without using any Dichlor initially (so no CYA in the water), then this would be far, far worse than anything in the list. Also, something not shown in the list would be using a small amount of MPS daily as that might reduce or even eliminate monochloramine formation so might be close to the 1/2 categories -- the downside being that MPS can be irritating.

According to some breakpoint chlorination models (and with 4 ppm FC, pH 7.5, Temp 102F), having no CYA gets to 90% completion of breakpoint in around 4-12 minutes. With 20 ppm CYA it's around 47-69 minutes while with 100 ppm CYA it's around 3-4 hours. The longer it takes to complete breakpoint, the longer that monochloramine sticks around to be outgassed and work on corroding the cover material. Keeping the cover off for a short time after using the tub and added more chlorine will help prolong its life. Though this would make it seem that no CYA should be used so that breakpoint happens quickly, there are other problems with the disinfecting chlorine being too high. With no CYA the chlorine (hypochlorous acid) concentration in the water and the air is 20 times higher than with 20 ppm CYA. So the bottom line is that too little or too much CYA is not good so a balance is desired.

Richard