Hot Tubs

How to get rid of hot tub foam

How to get rid of hot tub foam

Before we get too far into things, its first worth checking if you really do have foamy water. If after turning all the pumps off, your foam is gone within a matter of seconds, its unlikely you have a problem, you just have a very powerful tub creating lots of bubbles!

If on the other hand you’re left with foam up to your eyeballs and its not going anywhere, you should definitely read on!

What is the foam in a hot tub?

Foam can be caused by a number of factors and its not always immediately clear which one it is and this can make fixing the issue particularly tricky.

Soaps and detergents

This is the most likely culprit and thankfully the easiest to fix. When having a shower before you get in the tub, make sure you have an extra good rinse and remove any sneaky detergents that are still on your skin or in your hair. This is also a good time to make sure that your bathing suit is 100% free of any residues as washing powders etc can be stubborn to rinse completely.

Oils and lotions

This is the next guilty party in your foam issues and its another simple to solve one, always have a shower before you jump in your hot tub. We know it feels like a extra step between you and relaxing, but the benefits are numerous, a cleaner hot tub, less chemical usage and therefore less running costs, plus an end to that unsightly foam!


This ones a bit tougher to solve, biofilm is a build up of bacteria on the surfaces of your hot tub and in your pipework, just like that green slime you see inside a flower vase. Don’t underestimate it though, its clever and builds a protective jacket around itself that protects it from your sanitiser and keeps it alive!

This eventually uses up more and more of your sanitiser, leaving less to deal with the other substances in your tub that cause foam.

Poor water balance

While getting the balance of your water incorrect will not cause foam on its own, it can exacerbate other issues that do. In particular, low calcium hardness can reduce the surface tension of the water and therefore create an environment for foam to thrive.

How to get rid of hot tub foam

The very first thing you should do is test your water to see where your levels are at and correct them if they are outside the acceptable parameters.

Next take a look at your waterline around the hot tub and the surface of the water, is there a visible build up of oils and scum? You may find that shocking the hot tub helps break down these contaminants and your foam issues subside. You could also try a scum sponge to soak up some of these oils.

If you need a quick fix for hot tub foam

You could try an anti-foam product, this will reduce the problem instantly, however it is only temporary as the effects tend to last for a day or so, before the foam comes back. However this is a great solution if you are getting the spa ready for an event for example and don’t have time for other methods.

A more permanent fix

The very best treatment is a complete drain and refill, at this point we would recommend you:

  1. Run a flush treatment
  2. Drain your tub completely of water and vacuum out the bottom with a wet vac
  3. Clean the inside surfaces with a dedicated spa shell cleaner
  4. Rinse the inside of the tub down to remove all traces of flushing chemicals
  5. Clean your filters
  6. Refill with clean water and remember to shock the water with a sanitiser to give you a clean slate to work with.

How to prevent foam in the hot tub

Prevention is a whole lot better than cure when it comes to foam as it can be really stubborn to fix, so with that said, we recommend:

  • Always showering directly before using your tub and making sure you rinse off thoroughly
  • Rinsing out your swimming costume in fresh water to remove any detergents
  • Maintain the correct water balance and keep an eye on your sanitiser level as this is the first line of defence.
  • Make sure to thoroughly rinse out filters after cleaning them, to remove any persistent detergents.