What to do when your hot tub water smells

A one minute tutorial


If the water is smelling, then in 99% of the cases you are smelling contamination which is due to low chlorine.
Either that or the filters are very dirty and/or your pH is not correct and the sanitiser can’t do its job properly.

Non-chlorine shock will break down oils but will not kill bacteria/contamination it helps the chlorine to work better so it works great in conjunction with chlorine.
If we assume that you are using a sanitiser (chlorine or bromine) but it is not working then it would be advisable to use chlorine shock (calcium hypochlorite) first in case you are not using chlorine at all at the moment.

This type of chlorine will work fast but it can be gone quickly too in case you have not been using that particular sanitiser.
You should add some and then measure….most likely you will have to use more after that if the chlorine dissipates within an hour or even quicker.
Don’t be afraid to use some more because it will kill off contamination in the hot tub (otherwise it would be left and you could measure it)

You need to measure some free chlorine after some hours to be sure you are getting there.


– When the water in your hot tub smells musty or stale, then check the basics…. start with the pH level and sanitiser level.

– In most cases, you’ll find that at least one of these is not correct.

When the pH level is off …. most sanitizers won’t work properly.
Set it between 7.2 and 7.6 and then correct the sanitiser value.
Run the pumps for a bit and wait a little while……the problem will most likely be solved.
At the right Ph levels, don’t be afraid to use a bit more sanitiser than usual because there is probably some contamination that needs to be dealt with.
Sometimes it can also be the filter that causes the smell so clean and replace it regularly.

A headshot of Natalie Lapierre against a black background
Article by: Natalie Lapierre

We hope you have found this information useful. If you have any further questions or have something to say about it, please waste no time in sending us an email at [email protected] or use the form on our contact page