How to lower the chlorine levels in your hot tub

Posted by Nick Clamp in Maintaining a Hot Tub Guides on 3rd June 2022

It’s easy to add too much chlorine when you’re adding sanitiser or shocking your home spa.

Luckily, high hot tub chlorine levels is an easy problem to fix as well.

Here’s how to spot if your hot tub’s chlorine levels are too high and three simple ways to lower them.

© Coast Spas

How to check if your hot tub’s chlorine levels are too high

Your hot tub’s chlorine levels should be between 1.0 and 3.0 ppm at all times.

Any higher and it will cause that strong “swimming pool” smell, irritate your eyes and skin, and can damage your hot tub’s components. Any lower and there won’t be enough sanitiser in your spa to keep it sanitary, which can lead to problems like foamy hot tub water.

So, be sure to test your home spa’s water every day with a hot tub test strip that measures chlorine levels as part of your hot tub maintenance routine

You should also measure sanitiser levels every time you adjust your hot tub’s chemistry, top it up with chlorine granules, or shock your spa with a chlorine-based shock treatment.

How to lower your hot tub’s chlorine levels

There are three simple ways to bring your home spa’s chlorine levels down if your test strip reads higher than 3 ppm.

Wait it out

Your hot tub’s chlorine levels will drop on their own over time. Your best bet is therefore waiting it out if you’re not planning on using your spa for a day or two. 

If you want to be able to use your spa a bit sooner, you can speed things up by running the air jets on full and leaving the cover open. This will encourage the chlorine to dissipate (especially if the sun is shining, as sunlight diminishes chlorine). 

© ERGO Group

Dilute the water

Removing a couple of buckets worth of water from your spa and replacing them with fresh water will lower the concentration of chlorine. Once you’ve done this, turn the air jets on and let the water circulate for fifteen minutes before dipping your test strip back in the water to ensure you get an accurate reading. If the chlorine levels are still too high, repeat the process until they’re under 3 ppm.

Use a chlorine neutraliser

Want to lower your hot tub’s chlorine levels fast? Simply add chlorine neutralizer according to the manufacturer’s instructions, run the jets for a few minutes to circulate it, and then test the water again to see if you need to add any more.

Summing up

Luckily, lowering your hot tub’s chlorine levels is as easy as it is to add too much in the first place. You can wait it out if you’re not in a rush to hop in for a soak, swap out some of the water with a few bucketfuls of fresh water to dilute it, or add some chlorine neutraliser if you have some to hand.


Whatever you do, just make sure there’s less than 3 ppm of chlorine in your home spa before you get in it so you don’t end up irritating your eyes or skin.

For more expert advice on buying, installing, and maintaining a hot tub – as well as our pick of the best buys for every budget – pick up your free copy of WhatSpa? magazine. 

About the author

Nick Clamp

I am the Editor-in-Chief at WhatSpa? Media Group and my job is to keep you informed about the very latest hot tubs on the UK market... the best job in the world! When I'm not being deluged with press releases and hot tub brochures I enjoy keeping fit and participating in endurance events including triathlons and distance running.

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