What Is The Scum In Hot Tub Foam?

What is the scum in hot tub foam

Soaking in a hot tub is one of the most relaxing feelings to experience. It provides you with mental and physical stress reduction relief. Hot water heats blood vessels, which sends nutrient-rich blood throughout your body. It also causes the tightened muscles to loosen up which makes you feel light and relaxed. While bathing in a hot tub, foams can form depending on the use of body lotion, suntan oil, or soap residue left behind or applied on purpose. You may have also noticed a thin line of rust-like substance over the foam layer or by the wall of the tub in parallel with the water line. So, what is the scum in hot tub foam?

Hot tub scum or lines are a formation of dirt and debris in your hot tub. It may have formed due to external foreign objects like dust or due to an internal supply of contaminated water, residue care products, bacteria growth, etc. Let’s discuss why this scum forms in the hot tub foam, their types, how to remove scum with a scum absorber, and ways to prevent them from coming. So read thoroughly to have an ultimate peaceful and scum-free hot tub soaking experience.

Key Takeaways

  • Scums are layers of colorful dirt-like substances that can grow in contaminated water.
  • Tub water can get contaminated with human byproducts, high pH, mineral metals, etc.
  • Tubs affected with scum can be cleaned easily by washing and refilling the tub with fresh water.
  • Blue-Green colored scum means your hot tub has been badly infected with harmful organisms.

The Scum in Hot Tub Foam

The scum in hot tub foam
The scum in hot tub foam

The scum in hot tub foam forms due to various internal and external issues. Usually, the hot tub water is filtered out to prevent any unwanted scum to grow. However, the filtration process may not always be effective in handling excessive bio and material contamination. It can cause layers of scum to float over the foam and may leave a stain on the tub wall. Here are some of the possible reasons for forming scum in hot tub foam:

Hair and skin cells

Astonishingly, each day our body flings away millions of dead cells into the air. There could be multiple layers of dead cells mixed with toxic body substances that are ready to be ditched. When we soak ourselves into the hot water, these dead cells get mixed into the soapy water. Also, a human can shed up to 50-100 hairs every day. In addition, body oil, and sweat add to the tally of materials released from the human body. All of this together contaminates the hot water and can make scum grow.

Personal care products

Apart from the materials our body disposes of every day, we use a variety of skin and hair products such as shampoo, conditioner, deodorants, perfume, and lotions to make our appearance look, feel, and smell good. These products are nothing but a group of chemical formulations that too disposed into the hot tub water while bathing. These products make several chemical reactions and cause foamy scum to grow.

Water metals

The water you are using in your spa tub mostly comes from underground mineral water sources. This water often contains other minerals such as copper, iron, magnesium, etc. Depending on your location this contamination can be much or less. On the other hand, we use chlorine to sanitize the pool water.  Once these metals come in touch with chlorine, they start to oxidize themselves, causing a greenish scum to form in the hot tub water.

High pH level

The pH level of water can greatly affect the cleanliness of any water. pH is measured on a scale of 0 to 14, from which 7 is considered neutral. If the pH is lower than 7, it can cause the water to be acidic. Similarly, higher pH levels can too cause scum issues. It is always important to keep the pH level balanced to have a natural and healthy soaking in a hot tub.

Dirty filter

One major reason your hot tub foam is contaminated with scum can be because the default water filter may be contaminated with dirt. The filter’s duty is to keep clean the contaminated water from internal and external sources. But at some point, the filter itself gets contaminated and loses its proper functionality. Hence due to improper ability to filter the water, scum can grow over your hot tub foam.

Types of Scum in Hot Tub Foam

It is important to know what types of scum you have in your hot tub foams. The color of the scum referees their class and lets you know what are the cause of their forming. Usually, there are three types of scum seen in hot tub foam:

Types of scum in hot tub foam
Types of scum in hot tub foam
  1. Brown Colored Scum
  2. Green Colored Scum
  3. Blue-Green Colored Scum
  1. Brown Scum: If the water pH is too high, it causes minerals like iron to react with chlorine. This creates a nasty brown scum. Also, a higher pH level makes the water suitable for growing algae and similar organisms to grow. It can generate brownish scum on the hot tub foam.
  2. Green Scum: Mineral metals such as copper, iron, and magnesium are responsible for such scum. High copper or magnesium level in the tub makes an opposite chemical formation against the already existing water-cleaning chlorine, causing a green-colored scum to grow.
  3. Blue-Green Scum: This is the worst of all scum. When metals, hair, and body skin wastage, personal care products in the water, and a dirty or worn-out filter join up against the fresh tub water, it causes to grow blue-green scum. It can be caused if your hot tub is being used excessively and the filtration isn’t at enough pace. Personal care products and faulty filters.

✨ You May like: What Kills Biofilm In A Hot Tub?

How to Remove The Scum from Hot Tub?

How to remove the scum from hot tub
How to remove the scum from the hot tub

Scums in the hot tub can be a disappointing scene to watch while you are soaking in a hot tub session. But there are ways you can apply to remove scum. Some of the methods for removing scum are:

Skim the water

The first step in cleaning your scum-affected hot tub is to simply skim off the scum from the water. If the scum is dense, skim off in passes to collect as much scum and other material debris. This process will also work as a further prevention of scum from floating debris.

Oil absorbing sponge

You can use oil-absorbing sponges to collect the unrequired oil and similar substances from the water. For this task, you can assign more than one tennis ball. The use of specifically made scum-absorbing sponges is likely to have a greater impact on removing the oil stains. You can find them in different lovely shapes and can be an amusing partner to bathe with. Just remember to wash it every few weeks or so if they are washable. If it is for one-time use, then dispose of it as necessary.

Clean & refill the tub

The most efficient way to clean the scum from your hot tub is to clean off the whole tub at once. If the scum floating visibility seems high to you then it is better to change the water with fresh ones. And unlike the other methods, this one is not as easy as you will need to follow some steps! Here is how you will clean and refill the tub:

  1. Switch off the tub before starting. Don’t use any water sanitizer before draining as it may add more buildups in the process.
  2. After draining all the water, carefully look into the tub from every angle to discover the placements of the scum.
  3. Check on the previous water line if there is any scum line or strain visible. Now take a hot tub cleaner and a fresh sponge to wash off the scum.
  4. After cleaning every point of the tub, rinse thoroughly with fresh water. Take time to make it dry then refill fresh water to be back in business.
  5. If the issue is a water filter, take it out and soak it in a filter cleaner overnight or use a high-pressure nozzle to wash it.
  6. Once everything is cleaned, refill the hot tub add chlorine to the water and wait 24 hours before you use it again.

How to Prevent Scum in Hot Tub Foam: 7 Tips

As mentioned there are several types of scum in hot tub foam and you can counter them from coming by following below methods:

  1. Keep The pH Level Balanced: To keep the hot tub from green scum, maintain the water pH level within 7.6. It will be pH-balanced water and prevent algae from growing.
  2. Shower Before Using Hot Tub: To keep the water away from your skin and hair products, it is wiser to take a quick shower before using a hot tub. This little effort will greatly help the tub from generating green-blue scum.
  3. Use a Hose Filter To Prevent Green Scum: While filling in the hot tub from external sources. Use a hose filter on the tip of the pipe to filter out the debris and solid materials. This will reduce scum vastly.
  4. Test Water Regularly for pH and Metal every week: In addition to keeping the pH level balanced and using a test kit. It will be better to check water elements by having relevant tests every week.
  5. Shock Your Spa Regularly: In parallel to using the hot tub, it is better to shake it once a week. This process will allow more oxygen to be generated in the water and remove bacteria, and impurities.
  6. Wipe The Hot Tub After Cleaning: Even after cleaning your hot tub, scum and such substances may remain accumulated at the bottom. For that wipe the entire tub with a fresh cloth.
  7. Keep Clean the Filter: The most important mechanism to keep the tub’s water clean is the water filter. Soak, spray the filter with tub cleaner, then brush off it properly, and rinse with fresh water. If the filter seems worn off, then replace it with a new one.


1. Are hot tubs healthy?

Studies have found that taking a hot tub soaking can help you to reduce mental stress and physical fatigue. It also helps to bring calmness to the mind, reducing the chances of heart attacks.

2. Is it OK to hot tub every day?

As per several expert opinions, using hot tubs every day can help you to reduce pain in your muscles and joints. You can also see improvement in better health, deeper sleep, and minor weight loss.

3. Who should avoid hot tubs?

Hot tubs come with an unusual lying position in the water. Users who have different seizures, are pregnant, have heart disease, and are alcohol consumers are suggested not to use such facilities for their inability to quickly respond.

Final Thoughts

To conclude, Scrums are rusty-dusty-like dirt substances that can grow in tub water due to human cells, hair, care products, mineral metals contamination, and pH unbalance. Soaking in a hot water tub is fun as long as the water is fresh. Because scum affected water provides a hint that the water might be contaminated with bacteria and other skin-damaging substances, although these scums are easily removable. Using clean water in a hot tub provides its user with a mind-refreshing clean vibe. You can also have such a pleasant hot tub experience in your backyard by keeping some easy preventive methods against scum.

✨ Next Attraction: What Is A Scum Absorber?

+ posts

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.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top