Itchy Skin or Sore Eyes After a Hot Tub? Causes and Fixes
Canadian Spa CompanyA soak should leave your skin feeling soft, not itchy, and your eyes shouldn't sting when you get out. When they do, the water is nearly always telling you something. In most cases the cause is the water chemistry, the age of the water or what's being carried into it, and each of those can be checked and put right at home in a day or two.
Stay out until you've tested
If anyone in the family has itchy skin, red patches or sore eyes after a soak, keep the cover on and don't use the spa again until you've tested the water. Most problems show up on a test strip within a minute. Our 3-in-1 Test Strips (£5.99 for 50) read free chlorine, pH and total alkalinity. Dip a strip, take it straight out, hold it level for 15 seconds and compare it with the colour chart. These are the ranges to aim for:
- Total alkalinity: 80 to 120 ppm
- pH: 7.2 to 7.6
- Free chlorine: 1.0 to 1.5 ppm
Correct them in that order, alkalinity first, because alkalinity holds the pH steady. Our step-by-step hot tub chemistry guide explains each reading and how to adjust it.
The usual causes, and what to do
A strong chlorine smell and stinging eyes
This one surprises people, because a sharp "swimming pool" smell usually means there's too little working chlorine, not too much. When chlorine has done its job against sweat, skin oils and cosmetics, the used-up chlorine stays in the water. That spent chlorine is what smells and what makes eyes sting. Not sure which smell you've got? Our guide to why a hot tub smells matches each smell to its cause. The fix is to break it down. Add Non-Chlorine Spa Shock (£25), which oxidises body oils and other waste the filter can't catch and gets your existing sanitiser working again without raising the chlorine level. Leave the cover open with the jets running for a while afterwards, then retest.
pH out of range
If pH sits outside 7.2 to 7.6, the water itself can irritate skin and eyes, and the chlorine works less well at the same time. High pH often goes hand in hand with scale on the waterline in hard-water areas, and pH Down (£15) brings it back. Add it gradually, let the jets run, and retest before adding more. If pH is low, use pH Up instead.
Too much chlorine
Overdosing does happen, usually after an extra scoop "to be safe". If the strip shows chlorine well above 1.5 ppm, leave the cover open with the jets running and retest. Don't get in until it's back in range. Next time, measure the dose rather than guessing it.
Too little sanitiser
Low chlorine lets bacteria build up, especially in warm water that's being used a lot. Bring it back up with Chlorine Granules (£9.99), with the pump running so they spread through the water. If the water is below 20°C, dissolve the dose in a plastic container of water before adding it. Then test more often for the next week, particularly after busy weekends.
Old water or detergent build-up
Every soak adds sweat, skin cells, cosmetics and washing powder from swimwear. Chemicals can only hold that back for so long. If you use our chlorine, pH stays stable once you've adjusted it after the first fill from the tap. So if your pH starts swinging up and down, it usually means there's too much detergent in the water, and a full water change is the best fix. Most owners change the water every 4 to 6 months, depending on use. Our guide to how often to drain and refill a hot tub walks you through it.
A tired filter
A clogged filter leaves more waste in the water for the chlorine to deal with. Rinse it regularly, give it a deep clean at each water change, and replace it on time: every 4 to 6 weeks for portable and inflatable spas, and every 6 to 12 months for acrylic hot tubs and swim spas.
Habits that keep the water comfortable
- Rinse off in the shower before you get in, so less body lotion, make-up and hair product goes into the spa.
- Rinse swimwear in clean water after use, and avoid washing it in strong detergent or fabric conditioner.
- Shower again after your soak and moisturise if your skin tends to be dry.
- Test the water two to three times a week, and again the day after a party or heavy use.
- Shock the water weekly or after heavy use, even if it still looks clear.
- Keep soaks to a sensible length, especially at higher temperatures.
If the water is also cloudy, foamy or green, our cloudy, foamy and green water troubleshooting guide covers those problems step by step.
Common questions
Is it the chlorine I'm sensitive to?
Sometimes, but check the readings first. Most irritation comes from water that's out of balance, rather than from chlorine at the right level. If the water tests in range and you still react, bromine is an alternative sanitiser that some people with sensitive skin prefer. It does need more frequent alkalinity checks, so ask us before you switch. Our guide to chlorine or bromine for your hot tub explains when bromine is the better choice for someone sensitive to chlorine.
The water looks clear. Can it still cause irritation?
Yes. Clear water can still have the wrong pH or a build-up of spent chlorine. That's why testing matters more than how the water looks.
When should I get advice about a rash?
If a rash or sore eyes don't settle within a day or two, if the rash spreads, or if you feel unwell, speak to a pharmacist or your GP. Do the same before using a hot tub if you have a skin condition or another health condition.
If you've tested, rebalanced and something still doesn't feel right, call Canadian Spa Company on 01293 824094 and we'll help you work through your readings.
A note on wellbeing: you shouldn't use a hot tub while pregnant. This article is general water care guidance, not medical advice, and the NHS website is the place to go for health information.