8 Reasons Your Pool is Foaming and How to Fix It

There is nothing quite as disappointing as stepping outside on a beautiful summer day and heading to your pool only to find it covered in a layer of foam. Pool foam can occur for many reasons, and fortunately, the resolutions to this issue are not overly complicated.

Pool foam is caused by the buildup of organic materials to a point in which the pool chemicals cannot dissolve them, creating bubbles perpetuated in a foamy layer. A few sources include personal care/hair products, moisturizers, detergent, non-pool cleaning supplies, and chemical imbalance.

Fortunately, there are both preventative and responsive methods for resolving pool foam, and the answers might surprise you with how simple they are. Still, it is important to understand how the pool foam might be getting into your pool in the first place so that you can tackle the problem head-on. To help you out, I have created a list of the top 8 reasons your pool is foaming as well as how to fix this issue. Let’s dive in.

1. Personal Care Products

When it comes to personal care products, let’s face it- not many of us break from our routine in choosing which products to use, and we especially do not consider if they are going to be tolerable in our backyard pool. For example, you likely think about your deodorant, makeup, soap, and shampoo as a way to freshen up, look and smell your best, and be presentable before your pool extravaganza, but you neglect to consider what it may leave behind.

Unfortunately, many personal care products contain contaminants that cannot be dissolved in pool water- even with the pool chemicals balanced well. This is particularly true if there is a high number of swimmers who are choosing to enter the pool- all with varying personal care products that they use.

What happens here is that the particular personal care product that you use on your body leaves behind a residue that is then sent into the water as you swim. This buildup in the water creates a layer of organic bubbles, so instead of the water forming the bubble’s shell, the residue left behind does this instead. 

Consequently, the bubble does not pop as easily because it is “protected” by a more sturdy material (aka the residue) than a bubble that is made entirely from water would be. Thus, the bubbles remain intact, and a layer of foam begins to gather on the surface of your pool. The more swimmers there are in the pool (especially at the same time), the more buildup is likely to occur.

2. Hair Products

Very similar in nature to personal care products are hair products that cause your pool to foam. These types of products could include soap and shampoo (as mentioned in personal care products), but they could also branch a bit farther into hairspray, hair gel, mousse, and more. 

The concept here is the same as above: the residue that comes from these products does not dismantle well and can build up in your pool causing a thick layer of foam. Hair products often have a more obvious influence here in the residue that they leave behind. 

Consider when you are spraying your curls and want them to last, or you are carefully placing your mouse to perfectly shape your luscious locks. As great as you may look and feel, it is obvious that there is some type of product in your hair, and if you were to run your fingers through it, it would be noticeable in any residue and the additional matting that can occur with excessive use.

Now, when you hop in your pool, the pool water is what will rush through your beautiful curls, causing them to (most likely) fall out of tact. Still, you should be more concerned about what substance is left behind than you should be about your hairstyle no longer holding up. After all, it is these products that can so quickly take over your pool and cause a large amount of the surface to be covered in foam.

3. Moisturizers

Now, you could argue that moisturizers (coming from lotion, conditioner, and hair products) could fit into the above categories, but it is arguable that these deserve their own mention because of the particular influence that they have on the residue left behind, both on your skin and consequently in the pool water.

Moisturizers work to relieve the feeling of dryness on your skin and hair as they leave behind a substance that provides sweet, luxurious relief. However, just because your legs have been lotioned up and are as smooth as butter, this does not mean that the moisturizer that you have chosen to use is not going to leave behind its mark on your pool. 

Interestingly, moisturizing lotions, hair products, and personal care products are more prone than their non-moisturizing counterparts to create residue that forms pool foam. This is because they were technically designed to leave a product “behind” on your body or hair’s surface. However, you could see why this would be difficult in avoiding the creation of pool foam. 

Keep in mind that this could even be relevant to the particular sunscreen that you choose to use before entering in the pool. Because of this, not only should you apply the sunscreen and wait the recommended amount of time before entering the pool to keep your skin protected, but this helps the amount of residual sunscreen on the top of your skin to soak in rather than to become immediately washed into your backyard pool.

4. Laundry Detergent

Now, I am going to go ahead and guess that you are not dumping laundry detergent into your pool. Not only would this be entirely ridiculous, but it would also be pointless and could create prolonged damage to the balance of the pool water’s chemicals. Still, this is not the only way that laundry detergent could harm your pool (or the likely scenario, either).

Laundry detergent can cause your pool to foam because of the residue that it leaves behind on your clothing (and body, consequently). What happens here is that the laundry detergent that leaves your clothes smelling like an island breeze can leave behind a residue- and most do. While this is not noticeable to your touch (or shouldn’t be at least), you know that this is true because of the particles that cause you to be able to smell that delicious scent. Interestingly, products with fragrances are even more prone to leave behind residue for this exact reason.

Still, this residue stays on your clothes, which could include your bathing suit that you are wearing into the pool. And, even if you are not wearing a bathing suit that has been recently laundered, you can still expect some of the residue from the clothes you were wearing before going swimming to be on your skin. From here, they can be transferred into the pool water causing organic particles to create bubbles yielding a layer of foam in your pool.

5. Cleaning Supplies

Yet another (possibly surprising) reason that your pool may be foaming is due to cleaning supplies that were used in or around your pool’s surface. Typically, this should not occur with cleaning supplies that are designed for pool use, but you should avoid using cleaning supplies not designed for pool use if you want to avoid a layer of foam building (among other concerns).

It might seem strange that products used to clean surfaces near (or that come into contact with) your pool could be causing it to foam. Nonetheless, this can easily occur. What happens is that the cleaning supplies (not designed for pool use) may be used to clean the cover or sides of the pool or even used on toys or flotation devices that are brought into the pool by swimmers.

Once these come into contact with the water, they can not only leave behind a residue that can cause foam to begin to build (and remain for quite a while), but they also disrupt the chemical balance within the water. When this happens, the chemicals you would typically use to maintain a balance in your pool either cannot perform as they are designed to, or they have been overpowered by the chemicals in your cleaning supplies.

Because of this, using cleaning supplies that are not intended for pool use should not be used unless you want to encounter a large layer of foam (or find yourself struggling with other issues that have resulted as a consequence of this, too). This is true for any product or device that might be near the pool or enter into the pool (like a flotation device as mentioned above). 

6. Chemical Imbalance

Yet another reason that your pool could be foaming is due to a chemical imbalance (caused by a variety of reasons). Now, this might not be as easy to test for considering the varying chemicals that are used to maintain a pool’s cleanliness, but you can take a guess that this is causing the issue from a variety of common scenarios.

For example, when you are first cleaning your pool using an initial pool chemical kit during the late spring (as you prepare to open your pool for the summer), you may notice that you see a foamy layer forming on your pool. This could be the same in the late part of the summer as you begin to prepare your pool for the winter (or, winterize your pool, in other words). 

These scenarios are extraordinarily common considering that they take place during times when the buildup of organic matter is likely to be the most robust. Consequently, you are more likely to see the chemicals “working harder” to neutralize the pool to create a safe and sanitary area for swimming.

There can be other scenarios that this can occur, too, though. This can happen when chemicals are used near the pool that are not intended for pool use, when the calcium levels are too low, or if the chemicals that were used were too cheap and contained inadequate ratios for appropriately cleaning the pool. Consequently, you will want to make sure that you are using pool chemicals that are reputable and balanced according to standard test measures.

7. Cheap Algaecide

Another more specific note on how a chemical imbalance can cause you to experience foam in your pool comes up when you are using cheap algaecide. Now, this is not to say that just because your algaecide was found at a really great price means you will experience these types of issues. However, if you found your algaecide at a bulk store that does not specialize in pool equipment, you might consider if it is high enough quality to be used for your pool’s maintenance.

For example, some really cheap (not just inexpensive, but cheaply made) algaecide contains metal. These components, while they can help to reduce the algae growing in your pool, can consequently get stuck in the water causing it to “thicken”. In this instance, the matter could create the bubbles that would cause your pool to experience a layer of foam.

Interestingly, with algaecide, you might be in the clear to wait for a little while to see if you need any other intervention. Often, inefficient algaecide might just take a bit more time to clear up, leaving your pool without the foamy substance that is bothering you. However, if you have waited several days and are still noticing foam, then you might need to take another intervention.

8. Too Low of Calcium Levels

Yet another more specific chemical imbalance that is commonly experienced (and consequently can lead to foam in your pool) is when your calcium level becomes too low. What happens here is that the little calcium in your pool will effectively make your water softer. This, consequently, creates water that is more likely to foam from the start (before we even talk about bringing in residue and chemicals).

Alternatively, if your calcium level is too high, you could experience calcification making appearances on your pool wall through hardened gunk. Among other issues, you can see why the appropriate level of calcium is essential to achieve in your pool. Without this, you could be setting yourself (and, more importantly, your pool) up for some serious complications.

How to Fix the Issue of Foam in Your Pool

Now that we have taken a look at some of the top reasons your pool might be foaming (be it personal care products, laundry residue, chemical imbalances, etc.), it is time to take a closer look at how to resolve this issue. Specifically, what should you do once you have narrowed down the culprit that is causing your pool to foam (and do you have to narrow it down first)?

There are a few simple ways to fix foam in your pool. In most cases, you can start by shocking your pool. You can also use targeted products like anti-foam or calcium hardener depending on the issue. Preventative measures include rinsing before entering the pool and using fragrance-free products.

When it comes down to it, you may not know the culprit that is causing your pool to foam. For the most part, that will likely be ok still, and your resulting choices to resolve the issue will still likely be similar. 

Wait for Algaecide to Dissipate

That is unless the problem is with your algaecide. If you are experiencing issues with algaecide causing your pool to foam, it will likely dissipate, but it can take a few days to do so. In this case, if you think this might be the issue (because you recently added algaecide), then you should wait a few days to see if the foam subsides. If it does not, then you can take another step.

Shock Your Pool

In most cases (besides algaecide), you can resolve your pool foam by shocking your pool. Of course, this will mean that you cannot enter the pool for a while, but it gives your pool the great reset that it needs to restore balance to the chemicals as well as to eliminate any foam or other organic matter.

Use Targeted Products (ex. anti-foam or calcium hardener)

If shocking your pool does not reduce the level of foam (or you do not anticipate that this will help), you can try more targeted products. For example, if you believe that a low calcium level is the culprit for your pool foam, try adding a calcium hardener until you have achieved the right balance.

Then, if you are looking for a quicker resolution to getting rid of the foam than shocking your pool (such as if you have guests arriving in a few hours who will not be able to wait until your chemical balance has been restored), you can use a water-based anti-foam product that will not disrupt the chemical balance but can attack the gnarly little foam bubbles atop your pool water.

Take Preventative Actions (ex. Rinsing off and using fragrance-free products)

Finally, once you have gotten rid of the foam, you will want to consider taking preventative actions to eliminate residue from entering into your pool in the first place. One of the best ways to do this is to require all swimmers to rinse off beforehand. This helps to get rid of the residue from many of the above-described culprits that could be lingering on the swimmers’ bodies.

You can also invest in fragrance-free products such as laundry detergent that is fragrance-free. Typically, since the fragrances are one of the major causes of left-behind residue, eliminating this can be safe for your pool, and more importantly, your skin.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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