New Salt Water Spa...Rash...

by Randy
(Raymond, NH)

We bought a new hot tub, to replace an old cheap one. After it was filled (water is from my own well), I was careful to do everything right. I got the TA between 80 – 120 ppm, and has been stable.

The pH has also been on target and I put a water softener pillow in for about a half a day and brought hardness down to 50. I noticed with the test strips that came with the spa, that the first pad is for TBr, and that has been hovering around 5 at the beginning, and later is showing more like 10.

The free Cl was weak for the first couple of weeks as I was trying to get the feel of how things worked, and was around 0.5. I now have TBr around 10+, and FCl between 3 – 5, all else is stable and in range.

Here is my problem…

For the first 2 or 3 weeks, I could sit in the spa with the temp around 97 – 100 for a long period (1 hour plus) and had none of the skin rash problems I had in the past. As time passed, I started to get a little rash, and got worse with time.

I stayed out of it for almost a week to let the rash clear up. Last night I went back in it for about 45 minutes, and showered afterward. In a couple of hours, I had a noticeable strong rash. I have read extensively about “spa itch” where a certain bacteria grows in the hot water, and saw pictures of what it looks like. What I get is similar but not quite the same, not so red or with pus.

And last night it took 1 or 2 hours to develop, rather than the 2 or 3 days it takes the bacterial infection to develop. I am thinking something is accumulating in the water, but I don’t know what. Here is what I am using to add to the water:

I have been using Leslie’s Fresh and Clear shock, to shock the water after use, and the amount has been 1 ounce each use.

This is the one thing that has been consistent even with our past Jacuzzi. Natural Chemistry brand Clean and Perfect all purpose spray cleaner, for the water line scum that collects, and Spa Perfect, an weekly enzyme water treatment. Both of these are new to the use of this spa. I used the Fresh Waters pH/ Alk down initially to get the water balanced, and have used the “up” in small amounts to adjust up as needed. I used the same brand “spa metal free” at the beginning too.

Needless to say, I am a bit bummed out after spending 7K on a new spa, and I am back to getting a rash. My wife can go in with no problems, so I guess I have a sensitivity to something, perhaps the shock as that is the one common thing at this point. I am looking to you for advice.

I can bring in a water sample for testing, I think we need to be looking for something beyond the norm of the test strips. If you can recommend anyone with extensive water testing capabilities, I am certainly open to that!

Thanks for the question Randy

The title to the question is for a salt system hot tub, so we'll start from there. It didn't mention the amount of salt you're using or the amount that the chlorinating cell needs to properly sanitize the hot tub.

I would first check the manual or call the manufacturer of the chlorinating cell to see what range is needed for the salt. The salt cell at the YMCA hot tub has a pretty forgiving range, between 3200 - 4800ppm. Be sure you're in range for the kind of cell you have.

I would recommend getting a Myron Analog Salt Meter (a little pricey but worth it) from TMI Salt Pure. They're based in WA state and can help with your questions. I've personally been dealing with them for years and they're great.

You can see a picture of the salt meter at this link:

Salt Water Swimming Pools

Also check out this page:

Chlorine Generator

Also be sure the cell is dialed in right so you're getting the correct amount of chlorination. Next, your well water might be contamniated. You can either take a test reading to your local pool store and have them test for heavy metals such as iron and copper, or buy strips online. They're called Watersafe WS425W Well Water Test Kit.

Watersafe also has strips to test for bacteria. This is Watersafe WS-359RC Pool & Spa Bacteria Water Test- 10 pack.

Spa, Pool, and Hot Tub Maintenance

It sounds like the sanitizer at 10+ might be too high. Bromine should be kept between 3 - 6ppm. The heat eats up sanitizer quickly so you want to keep it a bit higher.

97 - 100 degrees is fine for extended periods, but I would encourage you to not go over that. We've found that after about 15 - 20 minutes at water over 103 degrees people start to get dehydrated and their core temperature goes up too high, so monitor your time in the hot tub.

Using CPR, I've had to revive several people when they collapsed after spending too long in the YMCA's hot tub. I would also encourage you to get an FAS-DPD K-2006 Reagent Test Kit from Taylor. It's the one I've used for years and the best on the market. It will give you the most accurate reading.

Water Testing Kit

Pool Water Testing

You'll test for chloramines. This will tell you when you need to shock the hot tub. 0.6 for three consecutive days is the range I've always used and it's never let me down.

Pool Shock

Chlorine Demand

The products you mentioned are great and do a wonderful job in keeping hot tubs clean. If you've used them in the past and have never had any bad reactions I would say keep using them.

The questions says that you're shocking the hot tub after every use. That may be a little excessive. Only after heavy use and after a good chlorine/chloramine test should you shock.

If the Natural Chemistry brand Clean and Perfect all purpose spray cleaner is new to you, you may want to stop that until you get the possible bacteria question handled. I can't diagnose any condition. You can always seek professional medical opinions. It might be classic hot tub rash or a chlorine allergy.

Chlorine Allergy

What is accumulating could be a quick build-up of chemicals. Get the FAS kit and other test strips mentioned above. If after all those check out, see your doctor who can run the proper test for hot tub rash or a chlorine allergy.

Hope this helps and good luck with your spa


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Oct 20, 2015
Issues still
by: Anonymous

Do you still have the same issue? I am having the same problem.

Feb 08, 2015
What I Found Out About Rash
by: Anonymous

I have a hot tub at the lake and had no problems for 10 years. Then I ended up with small red bumps mostly around the stomach area. They can get very itchy almost causing a fever like feeling. I finally found out it was the bromine or chlorine causing my skin to react almost like a dermatitis. I have an ozonator and shower before getting in the tub and experience no bumps.

If I go for a swim in the ocean the same thing happens. My doctor says it is a reaction to the chlorine, bromine or salt. He prescribed glaxal base cream which I apply immediately after getting out. I try to have a shower right away with cool water and then apply the cream. It does seem to help. I think my skin which is normally dry has become very sensitive to the salts or bromine.

Jan 15, 2015
What Do I Do About Salt Water Spa..Bad Rash..
by: Randy

I have had my water tested recently, and was tested for everything except the kitchen sink! The tested parameters cover two and a half pages, and also looks for any solvent and chemical residues, as well as bacteria.

I am fortunate to have good water. Recall my wife (and others) can go in the spa with no ill effect. The 10+ reading on total bromine is odd, there is NO bromine in this spa.
I was advised to disregard that by the dealer and make sure the free chlorine on these Freshwater brand test strips is in range.

I was told to use the "boost" function on the salt generator, which is an option called "Ace", on Hot Springs spas.

I have since drained and refilled the spa, and will use none of the non chlorine shock, as I suspect that the most. In researching the shock, one of the components is potassium persulfate. This chemical in particular is listed as a severe health risk, and is known to cause cause the type of skin rash that I have been getting.

The rash I have had does not have the characteristics of a bacterial type rash. Nor does it look at all like the example of chlorine allergy rash you posted. The information further states that persulfate allergy is not uncommon, and people with this allergy will develop a rash when exposed to this chemical.

Naturally this chemical may increase in concentration in the water over time, I did not have the problem in the spa after it was newly filled with water. The amount of salt used in this 325 gallon spa is 1.25 kg, and the test strips put the concentration at 1250 ppm.

I will go in the spa later now that it is refilled and all water parameters are where they should be. I will report if the rash comes back without using the non chlorine shock over the course of several days.

Nov 05, 2014
Follow Up On Rash
by: Anonymous

I have same problem. Salt water spa. Water checks out great. Rash with no pus. Wife and daughter no problem.

What have you found out ???

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