How to get rid of foam in hot tub - hot tub with no foam because of proper PH balance

Hot Tub Foam is no fun!

When you have a hot tub, foam is one of the most annoying things that can happen. It’s not only an inconvenience but it also leaves your hot tub looking dirty and unappealing.

Luckily, there are ways to prevent hot tub foam from happening in the first place. There are also anti-foam products that you can buy. These products will quickly, but temporarily, fix your foam problem.

To properly deal with hot tub foam, you will need to know what causes it and how to treat it. In this blog post, we will discuss what causes the foam to appear, how to prevent it from occurring, and how to get rid of it if it does occur!

Anti-foam for Hot Tub Foam Problem

Anti-foaming agents work quickly to dissipate foam. They will almost immediately eliminate the foam in your hot tub. This can be ideal for someone who is crunched for time and just needs a little while longer to properly deal with foam.

This can also be a quick save if you will be expecting guests in your hot tub and just need to eliminate foam quickly before using your spa. 

This is not a permanent solution! The foam will come back but this works great in a pinch.

You can even scoop out the foam with a cup or with your hands to help you see the water and begin the work of getting your water to the right PH Level.

PH Levels

The pH level of hot tub water can cause hot tub foam. The pH level should be kept between 7.2 and 7.8. If you notice your hot tub getting foamy, consider lowering the pH level by adding a pH decreaser, also referred to as Dry Acid. Never use Muriatic Acid to balance off the Ph factor in an acrylic hot tub. 

You may find that your hot tub PH level is too low. In this case, you will need to increase it by adding soda ash or baking soda. We recommend sodium bicarbonate as it allows for more of a gradual increase. Soda ash causes PH levels to rise quickly and is better for pools.   

Proper water chemistry is a vital part of keeping your hot tub water healthy and foam-free. You should test your water a least once a week to make sure that your tub water is balanced. 

It is best to speak to your spa dealer before using any products in your hot tub. They will be able to assist you in the best products for treating your brand of hot tub. 

Use PH Down hot to chemical to get rid of hot tub foam

Skin Products and Soap

One of the most common causes of hot tub foam is the use of skin care products and soap. When these products enter the hot tub they add oils and detergents to the water which can cause excessive foam. 

There are hot tub cleaning products that you can use to help absorb and eliminate these oils, which will in turn prevent or fix any foam caused by lotions, oils, detergents etc. If this is a recurring issue in your tub, there are some small things you can do to prevent the build-up skin care products and soap.

  1. Use spa-safe skin products that are free of oils.
  2. Rinse your swimwear thoroughly after washing, they can have trace amounts of detergents and fabric softener that will get in your hot tub water.
  3. Use an oxidizing shock to help eliminate organic build-up and help the chlorine work more effectively.
  4. Implement a spa enzyme to help keep oils in check. We recommend a spa enzyme, such as Natural Chemistry’s Spa Perfect.  It biodegrades soaps, oils, lotions, etc. and eliminates the need for floating oil absorbers. Spa Perfect also continuously helps break down these contaminants and prevents the filter from clogging.


Low calcium hardness can also cause hot tub foam. If hot tub water has a low calcium level, it will become “soft” and unable to hold on to the oxygen needed to oxidize body oils and the hot tub surface which causes the foam. The decrease in surface tension also aids in foam formation. 

To fix this issue you can add calcium chloride to the hot tub. Never use Cal-Hypo in an acrylic hot tub.

Calcium is necessary for pH and alkalinity stabilization. It is important to test your water using hardness testing strips.

You want to keep your calcium levels between 150-250 ppm. Anything over 400 is a cause of concern. At over 250 it may be a good idea to use a spa stain and scale on a weekly maintenance basis. Anything below or above this will begin to cause problems with the water in your hot tub. 

Our Most Popular Hot Tubs

Clean your filter

You should be sure to rinse your spa filters once a week. This can help to cut down on any oils or soap residue that may be circulating through your hot tub, helping to prevent future foam. Your filter should be changed every 3 or 4 months.  If you are using your hot tub heavily it is possible that you may need to change it more than that!

Draining and Refilling Your Hot Tub

You should be draining and refilling your hot tub water every three to four months depending on how many people use your hot tub and how frequently. Draining and refilling your tub gives you fresh water to work with and completely resets your water situation.

You’ll also want to be sure to wipe out your tub using a soft cloth and warm water. Don’t use an abrasive scrubber or any harsh chemicals, as this can damage the acrylic. It also will leave behind residue that will get into your new water.

You should also consider using a spa purge once a year.  A build-up of biofilm can also lead to foaming issues.  To use this product, you would maintain the spa water at a minimum of 95 degrees and remove the filter.  You would pour in the 1-liter bottle of Spa Purge and allow to circulate through the system (using your normal spa filtration settings) for approximately 12-24 hours.

Then you would drain your spa and refill. 

This is enzyme-based and will biodegrade any biofilm that has attached to the internal plumbing, allowing for a very productive drain.

You can do the same thing if you have a dual temp swim spa with a hot tub and swim spa in one unit!

Have more questions about hot tub maintenance? See this article on how easy it is to maintain a hot tub!

Hot tub foam can be a hassle, but through proper hot tub maintenance, you can prevent it from occurring. If you do find yourself faced with tackling hot tub foam issues. Don’t worry, it can be taken care of easily with the methods listed above. Regular water testing and keeping up with your chemical routine will go a long way to ensuring that your hot tub stays foam-free. 

It is always best to talk to your hot tub dealer before using any new products in your tub. This ensures that you can enjoy a nice relaxing soak in your tub for a long time.

Happy soaking!