Why Does My Swimming Pool Have Foam?

Swimming pool foam can be a huge distraction in and outside of your pool. Foam, or bubbles, make the water feel sticky and can make swimming uncomfortable for some. Good news for the kids, though, a foamy pool is safe to swim in. Still, we always recommend getting rid of the foam as soon as possible.

But, how did it get there in the first place?

This blog dives into what causes pool water to foam and explains how pool owners can prevent foam from forming. 

Why Does My Swimming Pool Have Foam?

If you’re reading this blog that means you’re asking yourself the same question, “Why does my swimming pool have foam?” Foam in pool water actually forms from a number of reasons.  So, we won’t be able to pinpoint your exact cause without running through the list.


click here to find your pool chemicals


Question One: Have you added any chemicals to your pool recently?

If you answered yes– what kind of chemicals did you add?  On occasion, pools can foam after pool owners add algaecide to their water. Whenever pool owners are searching for an algaecide, we always recommend purchasing a good one ($$). And yes, sometimes that means skipping over Walmart.

Make sure you check the bottle of algaecide, as well. Stay away from algaecides that contain copper or any unnecessary metallic. Cheap or algaecides containing metals can cause your pool to foam and you should avoid them.

In addition to watching the type of algaecide you’re using in your pool, also pay attention to the amount you’re using. If you overuse algaecide, it can cause foaming. We always recommend following the suggested dosages listed on the bottle.

Lastly, pay close attention to the chemicals typically sold in spring opening kits. If you add a pool opening kit to a well-maintained pool, it can cause your pool to foam. This happens because there are no algae in your pool to destroy. Springtime algaecides use surfactants to work and these molecules react with agitation causing froth.

** If the foam in your pool is caused by the type of algaecide you used, it should break down on its own. To speed the process up, you can skim the foam off the surface of your pool.


Question Two: Have you balanced your pool recently?

An imbalanced pool can be the culprit to a lot of maintenance issues and foaming isn’t an exception. The first step to maintaining a clear pool is balancing the water. We recommend you to test your pool water and pay attention to your calcium hardness levels.

Have you heard the term “soft water”? If someone says their pool water is soft that means it has low calcium hardness. Soft water is highly susceptible to foam.

** If after testing your pool water you determine that your pool has low calcium hardness,  we recommend adding calcium chloride. Adding calcium chloride raises your calcium hardness levels and prevent more foam.**


click here to find your pool chemicals


Question Three: Have you had swimmers in your pool recently?

Have you ever read that rule that swimmers should rinse off before getting into pools? How many of us actually remember to do this? Odds are, not many. The main reason we recommend rinsing yourself off before jumping into the pool is to remove any makeup, oils, shampoos, or other detergents.

These contaminants mix with the chemicals present in your water to produce foam. I know this rule can be tough, especially for little ones. However, by remembering to rinse off before jumping into the pool, you can prevent foaming.

If you’re experiencing foam or bubbles in your swimming pool and none of these questions help pinpoint the root- give us a call. We’d love to help determine why your pool is foaming.


16 thoughts on “Why Does My Swimming Pool Have Foam?

  1. Read many google entries about getting rid of foam. Thought I’d add what worked well for me and pass it on. I took a spray bottle with about a TSP of fabric softener, and filled the rest of the bottle with water. Spray it over the foam, then splash water to disperse the softener into the still sudsy water. Does not take much fabric softener. I kept filling the bottle with more water without adding more softener and apparently the little fabric softener still in the bottle continued to work. Only took about 1/2 hr for a 13×26 above ground pool, real quick. Thanks to everyone who takes the time to make notes like this to solve everyday problems by just googling the symptoms.

    1. I’ve never heard of this being done, so I can’t validate or invalidate it. But I like to stick to more conventional methods, just because this sounds like it would make more bubbles.

      I won’t be trying this on mine, but more than willing to do it on somebody else’s pool.

  2. My pool was clear yesterday I’ve only had it up 4 days. I put in a new filter today and it’s now full of foam makes no sense to me

  3. Many times people are quick to knock a product or solution. However, what works for one person might not work for another. As I often say it is a case by case bases. I service pools for a living and often hear I did this or they did that. Each pool is best treated on a case by cases bases. Over the past 20 years I learned you can never satisfy everyone by treating all the same. This is why people call pool service companies in the first place. #1 reason is they just want to swim and enjoy their pool. My advice is to let an experienced tech come out and get your pool working properly and once it is working properly, the owner can take over the process.
    As I always tell my employees never worry about trying to sell our service, our results proves our values. Often times companies worry about getting new customers and trying to keep them on the monthly billing cycle. I tend to differ with this thought and believe if you resolve the problem first and do a job correctly, the customer will choose your company over others.

    1. This may be true but I have opened and closed my pool for 31 years and never had a foam issue.
      I shocked my pool and put HTH algae guard in, I used clorox supper water clarifier and when I turn my salt chlorinator on at 40% the foam starts. May be to much algaecide

  4. “Whenever pool owners are searching for an algaecide, we always recommend purchasing a good one ($$). And yes, sometimes that means skipping over Walmart.” This is not necessarily true, I purchased a 1 quart bottle of Azure Algaecide 50 from INYOPools to use in my pool that stayed off all winter. I used it as directed but ended up using the whole bottle over the coarse of a week with little change in the swamp water. A few weeks later (due to the pandemic) I purchased a gallon of Clorox brand Algaecide from Walmart (this is what we used last time we had this issue) and the water was blue the next day. Mabey Azure brand wasn’t the correct choice but don’t knock Walmart right away. Do your research first.

  5. The fact you said Walmart brand should be skipped is not true. Since i was using that one my pool was perfectly balanced and no algae but when i changed it to pinch a penny one ruined my pool.

  6. I opened my pool yesterday and only turned on the pump and sand filter, it is a 20,000 in ground pool. The pump has run for less than 24 hours and this morning, is covered with foam. I am currently working to get the debris out-leaves-from the winter, and have not added any chemicals since we closed last fall. I do nto remember this happening last year when we opened. Any thooughts?

    1. My thoughts would circle back to most of the points mentioned in the article. As Charlie mentions in the section “Question One: Have you added any chemicals to your pool recently,”  Algaecide is commonly used while closing a pool. Did you use algaecide during the closing of your pool? If so, that could be the problem.

      In the very same section, this is stated:

      If you add a pool opening kit to a well-maintained pool, it can cause your pool to foam. This happens because there are no algae in your pool to destroy. Springtime algaecides use surfactants to work and these molecules react with agitation causing froth.

      Then the second section talks about balanced water chemistry. Is your pool’s water chemistry properly balanced? If not, then you also need to take care of that.

Leave a Reply

Your email address will not be published.

Recommended Resources

PSC Ep. 74: In what order do I add winterizing chemicals?

PSC Ep. 74: In what order do I add winterizing chemicals?

In today’s episode of Poolside Chat, Rob and Matt tackle another common swimming pool question:  I recently purchased a winterizing chemical...
Read Now

Why Is My Swimming Pool Foamy?

One of the most frequently asked questions when it comes to balancing the pool is “Why is my swimming pool foamy?”...
Read Now

Looking for pool parts?

Shop Motors Shop Filters Shop Pumps Shop Salt Systems Shop Lights Shop Cleaners
Copyright © 2020 INYOpools All rights reserved