What Kills Biofilm In A Hot Tub?

What kills biofilm in a hot tub

A hot tub is a perfect place to have a pleasant experience of bathing. Soaking in the tub’s hot water, not only nourished your body but also your soul. It deep cleanses your whole body and provides you with a fresh vibe. Imagine you are taking a similar hot tub session and in the process, you notice small buildups of scum-like substance floating above the water. You may mistake them as dirt at first glance, but at a closer look, you will find them as odorous, cloudy, dark substances.

If this is the case then you have most likely come across a pack of biofilms, which are the other organism that can grow in your hot tub. If you are wondering about how they appear, what can they cause, and what kills them in a hot tub, then you have found the perfect article to clear your thoughts about biofilms.

Key Takeaways

  • Biofilms form as a protective layer of shield for the bacteria formation to last longer.
  • Usual water purification ingredients such as Chlorine and bromine are not effective against Biofilm.
  • It takes enzyme-powered especially made sanitizers to remove biofilms.
  • Routine maintenance can prevent your tub from growing biofilms.

What is Biofilm and Its Role in Hot Tub?

What is biofilm and its role in hot tub
Biofilm and its role in the hot tub

Biofilms are a colony, a community of a pack of living organisms like bacteria. Biofilms are naturally occurring, everywhere. Algae on your hot tub walls is also a biofilm, but we are not about a more living structure of bacteria and other organic formations. They can emerge in a hot, humid, and moist environment such as a hot tub.

Though they are likely always discovered in the tub’s water surfaces, their emergence is likely on the pipe medium the water came into. The probability of growing biofilm in a water-filled, unused, unmaintained tub is also very high.

The main role of a biofilm is to cover the bacteria and other microorganisms from the preventive water cleaners such as chlorine, and bromine. To elaborate, in regular use, tubs of water can be affected by bacteria and other living organisms.

This organism is harmful in nature but doesn’t cause much danger as they are low in number. But still, we put sanitizers to remove them as much as possible. Biofilm works as a protective shield against these sanitized applications.

Role of Biofilm

They not only form a protection layer around the organisms but also make sure their future is protected against similar sanitizers. It is in the DNA of bacteria that they can reconfigure themselves against certain applications.

Biofilms further enhance that capability to the next level. In the presence of biofilm, the sanitizer attacks the outer layer of biofilm, leaving the bacteria in the core of it intact. The buildup of bacterial biofilm causes the water to be a foamy, cloudy, and visible oily ring at the waterline of the hot tub.

However, even though they are not that harmful to you (but would you really soak in one?), it is definitely harmful to the hot tub and pool equipment! The continuous contamination of water can cause the filtration system, pool skimmer suction, and the lining of the hot tub to deteriorate.

This is bad news because it will render your hot tub useless and a potential biohazard! That is why you need to make sure to kill the biofilm and get rid of it as soon as possible. To know more about hot tub problems, read this: Wellis Hot Tub Problems

What Kills Biofilm in A Hot Tub?

Biofilms are unwanted piles of microorganisms that have the capability to withhold normal sanitizers. That’s why it takes than better-than-average approach to kill biofilm. Some of those methods to kill biofilm in a hot tub are below:

All-Surface cleaner

If the biofilm buildups become very intense, the go-to solution will be to clean the whole hot tub area with an all-surface cleaner surfactant. For that, the hot tub needs to be completely empty.

Then sprinkle the all-surface cleaner throughout the hot tub and rub every corner thoroughly. Remember to clean the pipe nozzles as deep as possible, as they are the birthplace of such biofilms. At the end rinse with water properly.

Spa purge products

To prevent biofilms from forming, specific spa purging products can be used. These products specially treat the tub plumbing lines where the biofilms produce the most. Upon application, spa purging products create a sanitization foam that lifts the biofilms from different surfaces of the tub. To clear biofilms, you may need to repeat the process more than once as per the manufacturer’s instructions.

Filter cleaner

In addition to cleaning the whole tub surfaces including the water supply pipes, cleaning the filtration mechanisms is a must. You can soak the water filters with chemical cleaner for deep cleaning. Rinse water thoroughly to clean the solid wastes thoroughly. A well-functioning filter allows your tub to keep the water from forming biofilms.

Spa shock

Lower the pH level to 7.2 and stabilize the water to a normal temperature. Use twice or more dosages of non-chlorine spa shocks. Spa shocks allow oxidization in water to break down the bond between biofilms and remove any organic substance from the water.

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Why It is Important to Kill Biofilms?

Why it is important to kill biofilms
Why it is important to kill biofilms

Biofilms in a hot tub can pose several disadvantages. These cons can lead to malfunctioning the tub mechanisms to possible health hazards. Some of the important reasons to kill biofilms:

  1. Grows Harmful Bacteria: Hot tubs naturally provide a suitable environment for the bacteria to grow. It is hot, humid, and watery all the time. Biofilms assist such bacteria to grow and last long by providing a protective cover. These bacteria can often lead to health issues.
  2. Forms Scum And Algae: The presence of biofilms can encourage scum and algae. Scums are the formation of dust, debris, and human byproducts (dead cell, hair, skin oil). Algae are one type of plant-based biofilm itself. These organisms can disorient the normal watercolor and even spread odors.
  3. Clogs filter: Biofilms mostly start their journey from the water plumbing pipes. If not taken care of properly, they can grow in high numbers and lead to clogged pipes and tubs’ water filtration mechanisms.
  4. Possible Corrosion: Biofilms, as a bacterial colony can create extreme concentrations of corrosive agents such as organic acids. This hydrogen-formed corrosion process can lead to galvanic corrosion of the structure.
  5. Resistant To Traditional Disinfectants: Normal sanitizers such as Chlorine and bromine are of little to no use against biofilms. Rather their usual use to keep the water clean can create additional buildup in the water.

5 Ways to Prevent Biofilm from Coming Back

Prevent biofilm from coming back
Prevent biofilm from coming back

Biofilms are prone to regenerate even after the hot tub has been recovered from it. So it is better to take preventive steps so that biofilms may not occur in the first place or can’t return once recovered. Here are a few result-oriented tips you can follow to prevent biofilms from coming:

  • Balance Tubs Water: The pH level of a hot tub is a major factor for the scum, and biofilms to grow. Try to keep it within 7.2 -7.4. Use a pH indicator meter to identify the pH level accurately. If the pH level is low, then add soda ash or sodium bicarbonate to increase the pH value. To lower the pH, simply add a sufficient drop of lemon juice.
  • Shock Routinely: To prevent the forming of any unwanted organisms, foreign wastes, and other buildups, shock your hot water tub at least once a week. Frequent oxidization prevents anything from growing and keeps the water clean at the same time.
  • Keep The Filter Clean: Keeping the filter clean does half of the job of preventing biofilms. Wash the tub’s water filter with a general rinse every week and a chemical-soaked deep cleaning once every month. Don’t hesitate to change the filter if they have worn off after a long time of use.
  • Cover When Not In Use: If your spa hot tub is outside your bathroom then keep covering it up when in not use. Covering the tub will prevent dust, leaves, debris, rainwater, and other wastes from falling and contaminating the water. Use some of the Best Hot Tub Cover Lifter.
  • Drain And Clean: It is always better to reboot the whole system after certain times to keep it out of issues. Drain your hot tub once every 2/3 months and give it an extensive clean to remove any bacterial, or chemical buildups.


1. What is the best spa biofilm remover?

Biofilm is resistant to normal sanitizing products. You can use specifically designed biofilm cleaners, like AquaFinesse Spa Clean or Super SpaClean.

2. How to identify biofilms in my hot tub?

Biofilms create an odorous smelly, cloudy, and turbid appearance in the water. It can also create colorful bubble-shaped substances in the process. If you suspect any of such activities in your tub water then immediately start the cleaning methods.

3. Is Vinegar useful for removing biofilms?

Yes, vinegars are certainly capable of removing biofilms from hot tub water. But vinegar is an acetic acid and in the biofilm cleaning process, it will also reduce the pH level of water drastically.

Final Thoughts

Biofilms in a hot tub can be disturbing to discover. It has several disadvantages making the water cloudy and foamy, creating bacterial buildups, resisting normal sanitizers and the list goes on and on. It requires special materials, unique methods, and constant monitoring to identify and remove the biofilms from the hot tub. Even after removing them, one has to be vigilant to prevent their return.

Routine maintenance can keep your hot tub away from biofilms and also prevent their return once removed. Using deep cleaning products and cleaning methods, at regular intervals can ultimately kill the biofilms and provide you with a trouble-free hot tub session.

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I am Donald M. Beyer and I am backyard enthusiasts. I am a homeowner who has been doing DIY projects in and out of my house for many years. From simple backyard lunches to making an old-school pizza oven in my own backyard, I have a lot of experience in turning my backyard into my and my family’s personal playground.

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