Help – my swimming pool has foam

Foam in a pool can be a scary thing to see but, believe it or not, foaming is not scary.  It can be easily explained in a few ways and remedied with some patience.

foam in pool

Foam in a pool is due to the water being “thick.” This thickness creates bubbles.  The bubbles are filled with air that can come from your pool circulation system that return the water back into the pool or even the wind outside.


Common causes of foam are:

Hair care products – shampoo, gel, hairspray, etc.

Personal care products – body wash, lotions, deodorant and makeup

Laundry detergents or soaps

Household cleaners used on the pool cover, liner etc. that are not designed for pool use.

Chemical imbalances


The most common cause of foam in the spring is when a pool is opened and initial chemistry treatments are happening.  Foam can be seen winter wastes are gassing off – you are witnessing the chemical reaction. As the 6-8 months of organics are oxidized away with shocking (high chlorine, blended and powered oxygen all work well) the foam disappears.


Another common cause of foam is when your water is well maintained and a pool opening kit is added.  The algaecide in the kit can cause some foam if there is no algae in the pool to destroy – it lingers around with nothing to kill.  Spring time algaecides use surfactants to work and these molecules can react with agitation to cause froth.  The algaecide breaks down and uses itself up with time– patience is all you need to resolve this cause.


Foam can also occur when the pool has low calcium hardness.  Make sure you get your water professionally tested and adjust it to the recommended parameters.


Mechanical causes are the second most common cause of foam – if there is a little crack in any O-rings, seals, lids, etc. the pool equipment can draw air in the system that can cause foamy bubbles.  Take a close look at your return jets and if you see tiny microbubbles, or even bigger ones, take a critical look at how air may be entering the pool circulation system.  Make sure your filter is clean.


The thing about foaming is that you really need active partnership between yourself and your pool professional to test the water, evaluate your pool equipment and get to the cause of the foam issue.  The great news is that all foam issues get resolved – with time, water balance corrections, mechanical repairs or some anti-foam product

foam in filter

9 thoughts on “Help – my swimming pool has foam”

    1. That is a great question Joey – thank you for asking. So long as your sanitizer is testing correctly on your home test kit (1-3 ppm of chlorine for example), yes, the pool is safe to swim.
      I suggest taking a water sample to your pool care professional for full lab analysis to determine the cause of the foam and work with them on a remedy.
      Happy Swimming!

  1. Andrew Thatcher

    Hi there, i had a small algae bloom and then added a cheap algaecide. iknow, i know. right after that my pool started to foam. whenever i turn the hot tub on the amount of foam is crazy. it has been three weeks and it continues to foam. i am at my wits end and i am getting ready to drain the pool and start over. The water is super clean and i have done multiple shock treatments. no matter what i do it just gets worse. any advice would be appreciated.

  2. Hi,
    My pool doesn’t have foam or bubbles coming from the jets. But it creates an excessive amount of bubbles if someone jumps in or anything which is heavy enough to submerge is placed in. Is there a common cause for this symptom?

    1. Thanks for asking! The most common cause of what you are seeing is either:
      1. using too much of a ‘quat’ based algaecide – maybe think about switching to BioGuard Banish which does not foam:
      2. oxidize wastes more often – most pools need preventative care weekly – more if lots of swimming 🙂 – here is a great choice –

      Happy Swimming!

  3. Shonda Henderson

    I put an algaecide in my pool yesterday (I’ve been doing one algaecide one week and shock the next for preventative, they were out of the one I have been using so I purchased a different one. Said non foaming…but) shortly after it started to foam. I ran filter all night, woke up to a foamy pool. I backwashed, rinsed and tan filter for 12 hours to come home to even more foam in the pool. I read just be patient and it will subside, can you please advise on some guidance in this matter.
    Thank you in advance!!

  4. Hi so I have small traces of alge in my pool and I added a a dose of algicide to the pool (less than what is recommended for maintenance) and I’m still getting foam. It sits on top of the water it’s really aggravating to deal with. The one good thing that I benefit from the foam is it gathers any left over tanning products in the foam. But was wondering what am I doing wrong or what can I do to get rid of it and prevent future dealings with foam. Algicide used: HTH pool care algae gaurd. Pool shock used: HTH pool care chlorine granules ultra. Liquid chlorine used: pool essentials chlorinating liquid. Thank you in advance

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