How to get rid of biofilm in your hot tub

How to get rid of biofilm in your hot tub - Click to enlarge
How to get rid of biofilm in your hot tub - Click to enlarge
How to get rid of biofilm in your hot tub - Click to enlarge

Does your water look or smell weird? Maybe the water's cloudy, some mystery substance covering the surface of the water and/or near the jets and skimmer. Well that mystery substance is most likely biofilm. It's a bunch of bacteria secreting a protective layer of organic matter. Not only is it gross, it's also a health hazard, and you have to get rid of it before you let anyone use the spa. The purpose of this article is to explain why you have biofilm in your spa, how to get rid of it, and how to make sure it doesn't come back, because you really don't want biofilm in your spa.

Spas offer ideal conditions for bacteria to grow because of the combination of high temperatures and organic materials brought into the water by people using the hot tub. Over time, bacteria gathers in your hot tub, on your filters and in a thin film on the inside walls of your pipes. This film can be whitish, yellow, green, pink or black and it is generally goopy. Once it is established, it becomes much harder to maintain clear water.

Its appearance... and how to prevent it

The disinfection of your spa water is absolutely essential. Regardless of the type of treatment you use, you need to attend to it regularly.

If biofilm has appeared in your spa, it is most likely because your water treatment isn't regular or rigorous enough, or you made a treatment error. However, biofilm can sometimes be present even in new hot tubs, if the pipework stays damp after the final factory test.

Test your spa water as regularly as possible, to check the level of disinfectant, and act as quickly as possible if you find that the level is too low.

We advise new spa owners to perform quick daily tests to avoid the risk of having a major biofilm problem on their hands in the future. Biofilm starts to develop whenever there is no disinfectant in the water, and the more there is, the harder it is to get rid of. Some bacteria have generation times as short as 20 minutes in the near-perfect conditions of a warm hot tub, so if you leave your hot tub overnight with no disinfection, there could be a billion times more bacteria 10 hours later.

The best way to avoid the appearance of biofilm is to stick to regular testing and treatment, and of course to always take a shower before you use the spa.

How to get rid of it

Unfortunately, increasing the doses of your normal disinfection treatment, whether it's with chlorine, bromine, or active oxygen, is not the solution. Biofilm protects bacteria from these chemicals.

The best solution is to use products specifically designed to clean biofilm, like AquaFinesse Spa Clean or HTH SpaClean. The biofilm cleaner disintegrates the biofilm and brings it to the surface, but most importantly it cleans your pipes.

Don't forget to rinse your filters too, or even change them if they are very dirty.

You must then drain your hot tub and rinse the shell while the water level drops. All you have to do is fill the spa with new water, balance the pH and, above all, immediately resume your disinfection treatment, because most biofilm removers do not kill bacteria.


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