Hot tub rash

Lab Rat

Nov 23, 2021
Why am I the only one in my family that has developed a constant little red bump rash on my back and sides? Hot tub is brand new. After I went through a whole bromine conversion (which was even worse on my skin!) I did the Ahh some purge/full rinse and flush before filling and returning to chlorine in late Dec 2021. Water is pretty much crystal clear, odorless and perfectly balanced all the time since then. I use a 2-3 oz liquid chlorine (LC) and sometimes 2 tsp's dichlor granule sanitization routine daily (less Dichlor than LC to keep my CYA levels in check) Then a non-chlorine shock/oxidizer once a week. The ozonator seems to use up all the free chlorine daily? (4-5 ppm after daily application of LC then next day 0-1 ppm?) Am I allergic to or using too much chlorine? I never had a problem with heavily chlorinated swimming pools growing up. Is there another water enhancing product that anyone recommends? Getting to the point where I don't even dare to get in the thing anymore which is really a bummer. I almost bought into the 'Silk Balance" stuff but the price tag on that stuff is outrageous! Any advice would be greatly appreciated.

Lab Rat

Nov 23, 2021
I may have just answered my own question! Medications
Problem: Some medications can cause hot tub rash when you are soaking in hot water.
Solution: Consult with your physician to see if your medication may be causing the rash.


Bronze Supporter
TFP Guide
Jun 1, 2018
Hernando, Ms
Pool Size
Salt Water Generator
SWG Type
Intex Krystal Clear
Ditch the mps (oxidizer) & just shock with chlorine.
Mps is a commonly known skin irritant
Also some people get a rash from the high pressure of the jets.
Kinda like people who can scratch then get hives.


Mod Squad
Gold Supporter
TFP Guide
Jun 16, 2019
Hey Lab Rat. Glad there is a hopefully short term side effect going on.

Search for ahhsome purging here. New tubs are tested at the factory and drained, but not blown out. Even if it's an immediate ship without a 6 month warehousing somewhere, stagnant water sat in the plumbing and biofilms likely grew. They will cause a higher FC loss and also rashes like you described. On the plus side you didn't inherit a 10 year old tub by moving that's unimaginably worse, but get a small container of the ahhsome for spas/tubs ($35 ish) and run a few purges either now or at your first water exchange.


Well-known member
Sep 14, 2016
Coplay, PA
I second the "ditch the MPS", it just messes up your test results. Elevating Fc with LC does the same thing.

I am also a rash sufferer. Almost a year ago I developed a rash all over my back, sides, front and legs. Mostly on my back and sides though. Finally went to a dermatologist and I have Numular Eczema. It comes with age and dry skin basically. The first thing I would suggest is to get some Cerave moisturizer and put it on every time you get out of the tub. It sucks to keep up with it, but if you take a day or two off, you'll regret it. Hope that helps.
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