Biofilm Removal from your Spa or Hot Tub

bacteria-biofilmOver time the surfaces inside a spa and the plumbing can begin to accumulate excessive amounts of grime and bacteria called biofilm. Biofilm is a living organism, a slimy substance that is a combination of bacteria, dirt and organics.

Body oils, dead skin cells, lotions, cosmetics and more can become the base for biofilm, and then it begins to grow and spread on its own. It is most likely to develop in spas that do not have consistent water chemistry or very high bather loads and is usually found in areas of poor water circulation.

Biofilm is especially likely to develop in a spa that has been left with water in it without the filter system running for an extended period. If any moisture is left inside your plumbing, bacteria can thrive and spread. This is why biofilm is present in many jetted bathtubs as well, the bathtub is used, and then drained, and the small amounts of water left in the jets contain the building blocks for biofilm.

Oh My Heavens, if Spa Shock won't kill it, whatever shall I do? Biofilm is very resistant to sanitizers and difficult to remove. Cloudy water, foaming, and bad odors result, resistant to even heavy doses of regular and potent spa shock. If you have any of these symptoms, it is time to drain and thoroughly clean your spa.

Doing a deep cleaning on a regular basis will help to prevent biofilm from forming, and is the best way to completely remove it once it is present.


How to Deep Clean Your Spa

1. Remove and Clean Cartridge Filter Element

Filter Perfect for cleaner spa filtersSince you are going to spend some time cleaning the inside of your spa and clearing out your spa plumbing, this is a perfect time to soak the cartridge overnight with a cleansing solution. Filter Perfect is a great choice. If you don’t clean the filter you are going to be running clean water through a dirty filter allowing buildup to occur more quickly.

For tips and detailed instructions on how to deep clean your cartridge filter element check out Martin’s post “How to Really Clean a Pool Filter Cartridge”. Remember that spa filters should be replaced after about 10-15 cleanings, which comes out to be once or twice per year for most people.

2. Purge Plumbing Lines

This step is what will remove built up biofilm from inside the pipes in the spa.  This is critical – biofilm will build up in plumbing lines over time, and if it isn’t removed, it doesn’t matter how clean the interior of the spa is because water is flowing through biofilm filled pipes and bringing bacteria back in to the spa.

Before you purge the lines be sure to take out any removable spa pillows or any other accessories that might be in the spa, no need to coat them in purged biofilm!

spa-purge-for-biofilmBy adding Spa Purge and allowing your spa to circulate overnight you will draw out built up biofilm from the plumbing lines into the spa. If it is your first time doing this, or it has been awhile, I think you may be surprised how much muck and yuck comes out when using Spa Purge.

3. Drain the Spa

Now that we’ve purged all of the gunk from the plumbing lines into the spa, we need to drain the spa and deep clean the surface. Check your spa owner’s manual for specific draining instructions for your model spa; they can all be a bit different. lil-giant-water-wizard-cover-pump

Or you could always use a submersible pump, like the Water Wizard. This is quick and easy to use and will have most spas drained in a half hour or less, depending on the gallonage.

On average, spa owners drain and refill their spa about every 2-4 months. This can vary depending on the chemical balance in the water and how often the spa is used (and how many people are using it).

4. Clean the Spa

In The Swim Spa Care CleanerOnce you’ve completely drained the spa you will clean the interior surfaces. A soft rag should easily remove dirt from the hot tub shell. Pay extra attention to the water line where the most build up will occur. Our Spa Cleaner is a great degreaser and will not leave behind any residue.

Spa Pillows can be removed and cleaned with a mild soap and water solution or you can use the Spa Cleaner. If you do use a soap solution be sure to rinse the pillows off thoroughly to remove any soap residue. Since the rest of the spa will be sparkling, this is also a good time to condition spa covers with Cover Care.

If you have any questions about how to deep clean your spa, please give us a call at 1-800-288-7946. Do you have any spa cleaning tips for your fellow readers?  Leave us a comment below!

Jackie Wolski
InTheSwim Staff Blogger



Biofilm Removal from your Spa or Hot Tub — 2 Comments

  1. HELP!!Our tub is about a year old, we bought it used and have had it for 3 months. We have had trouble every since we had it with white flakes coming out jets. i just used purge on it and drained it. I have a question about purge. It may be a silly question but If these white flakes are biofilm which is a living organism and on bottle of purge it states it takes care of non living organisms. So will it work??if not, how do I get rid of the white flakes? I’m refilling hot tub now as we speak after we cleaned it but just want to make sure I do not run into this same problem. Do I need to do anything else to kill this biofilm?

    Also I had my water tested and will be adding proper chemicals in it once it is completely filled.

    Thank you in advance!!

    • Hi Jennifer – white flakes are usually a biofilm, or could be what some call ‘white water mold’, for which you may find more online advice, using white water mold as your main keyword. The Purge is a good step in the right direction. If it was my, I would plan on doing it more than once, perhaps with a very high chlorine shock in between the two Spa Purge treatments. Also I would recommend replacing the filter cartridge after treatment. This problem often occurs when tubs sit empty or stagnant for long periods of time. Unfortunately there is no physical way to scrub the inside of pipes, fittings and jets, so we use a ‘stripper’ chemical like Spa Purge, with high velocity water (Jets on high), to help knock the material loose. Keep good pH balance and high chlorine or bromine levels afterwards, and you should be able to enjoy this tub eventually.

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