Pool Foam

Pool Foam - What Causes It? How Do I Get Rid Of It?

Pool foam has an unsightly appearance that can make your pool seem dirty, unclean, or unsafe for swimming. Most pool foam is caused by a buildup of contaminants in the water, but there are also other causes.

In this article, we will discuss the different causes of pool foam, how to get rid of pool foam, and how to prevent pool foam from forming again in the future.

Causes of Pool Foam

Pool foam is caused by a variety of different contaminants. These contaminants all alter properties of the pool water, allowing foam to be created more easily. Not all causes of pool foam are a result of unsanitary conditions.

Cosmetic Products

Cosmetic products are those which are intended to be left on a person’s body. This includes makeup, but also includes all varieties of hair styling products, deodorants, body lotions, sunscreens, perfumes, and related items.

When swimmers enter your pool with these products on their person, chemicals from these products make their way into your pool’s water, introducing small particles of organic matter and chemicals that increase the likelihood of pool foam developing.

Hygiene And Laundry Products

Hygiene products, such as shampoo, conditioner, and trace amounts of body or hand soap can also cause pool foam. Likewise, any trace amounts of laundry soap or fabric softeners left on your skin or on swimwear can also end up in your pool’s water.

Unlike cosmetic products, hygiene soaps and laundry detergents contain high amounts of surfactants, a chemical which is used for cleaning and is known for its ability to produce bubbles.

In the wash, this is desirable as it aids the cleaning process, but once surfactants are introduced to your pool they can create foam when the water is disturbed (by splashing).

Low Calcium Hardness

Low calcium hardness levels in your pool can lead to an increase in pool foam. Low calcium levels and the resulting soft water creates foam in a similar way as surfactants; this condition lowers the surface tension of your water, allowing bubbles to be produced more easily.

Ideal calcium hardness levels in a pool range from 200-400 ppm (parts per million). To increase calcium hardness in your pool, use a calcium hardness increaser.

Algaecide Foam

Algaecide foam is a natural byproduct of algaecide usage. Because algaecides contain surfactants and also work to kill off living organisms in the water, these products are commonly known to produce foam for a 24-48 hour period following their addition to the pool water.

Luckily, foam caused by algaecide use will resolve itself as the pump runs.

Other Chemical Imbalances

Other chemical imbalances can also contribute to the production of pool foam, but this is more likely if other contaminants mentioned above are present.

To balance the chemistry in your pool, ensure that your total alkalinity levels fall between 80-120 ppm, your pH level ranges from 7.2-7.6, and you are maintaining ideal levels of sanitizer.

If you operate a traditional chlorine pool, ensure that your free chlorine levels fall between 2-4 ppm.

If you have a salt water pool, ensure that you are maintaining ideal amounts of salt that range from 2,700-3,400 ppm, and that your chlorine generator is producing free chlorine levels that fall within the range mentioned above.

How To Get Rid Of Pool Foam

Shock The Pool

Pool foam that is not caused by chemical imbalances or algaecide is typically caused by a variety of contaminants in the pool.

To remove these contaminants from your water, you should shock your pool. Some sources recommend a chlorine-based shock treatment, but non-chlorine shock products can be just as effective for this purpose.

To shock your pool, add the shock product of your choice and let the filter run for a few hours afterwards. More specific information about shocking your pool can be found on the packaging of the product of your choice, including how much product to use and how long to circulate the shock treatment before it is okay to swim again.

If you are in a hurry to use your pool again, or would simply like to avoid chlorine-based shock treatments for other reasons, we recommend Shock ‘n’ Swim.

This chlorine-free formula contains plenty of fast-acting oxidizers that remove foam-causing contaminants from your pool and sanitise your water, allowing your pool to be used again as soon as 15 minutes after treatment.

Check The Filter System

Occasionally, foam in a pool can indicate problems with your filter. Although this is much less common than the other causes listed above, many filter systems are capable of producing foam if a small air leak develops in any of your pool’s plumbing.

Check your filter system for small leaks that may be allowing air into your lines and creating excess foam. It is also a good idea to clean your filter cartridge by backwashing it or using a power nozzle where applicable.

Preventing Pool Foam In The Future

Encourage Clean Swimmers

The best way to prevent pool foam that is a result of water contaminants is by encouraging clean swimmers.

To do this, suggest that swimmers take a shower or at least rinse themselves off before entering the pool. If this seems like too much of a bother for your family or guests, there are other options available.

Shock Your Pool Regularly

So long as swimmers are still entering the pool without rinsing off, contaminants are slowly being introduced to your water. By shocking your pool regularly, you can minimise the buildup of contaminants that collect in your pool and cause foam.

To prevent pool foam, we recommend performing a maintenance shock treatment once a week, especially if you regularly have a high volume of swimmers. Alternatively, you can choose to shock your pool following more crowded swim sessions in order to tackle the new contaminants immediately.


Pool foam is unsightly and can ruin the swimming experience of your pool. Luckily, ridding your pool of foam-causing contaminants tends to be a fairly easy process. Once you have learned about the causes of pool foam, it is an easy condition to treat and prevent.

Do you have any questions about the causes of pool foam or how to get rid of it? Let us know in the comments, we’d love to help!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.