Being a pool owner comes with a lot of maintenance and hard work. However, once you get the hang of it, you fall into a routine that keeps your swimming pool healthy and swimmable at all times. Sometimes, though, despite your routine, you can run into trouble, like developing pool foam.
Though it looks gross, you don’t have to freak out about your pool developing foam. While it’s not a completely natural process, there are easy, quick solutions that allow you to combat and prevent swimming pool foam from further developing in your pool.
What is Pool Foam?
Foaming shows a pool’s health—or the lack thereof. Looking at your pool, you’ll know the difference between bubbles and foam intuitively because something just won’t look right with pool foam. It’ll be thick and remain on the surface while bubbles don’t do that.
Foam shows up on the surface of a pool when the water is “thick.” A few different factors can cause this “thickness” of the pool water—some human-made, some purely from a chemical imbalance. We’ll go over all the different causes of pool foam and how to combat them.
How is Pool Foam Different from Air Bubbles?
Bubbles occur naturally, or at least they appear underwater and get pushed up to the surface when jets are running. So how can you tell whether it is foam or bubbles? Foam can appear in patches or even a thick layer when jets aren’t running and stays floating on the surface.
This is where “thickness” plays a role as well. Bubbles are light and airy with little surface tension. On the other hand, foam is thick, dense, and does not pop as easily as bubbles because it’s a buildup of different organic materials and not air.
To be clear, bubbles aren’t that great either. Read my article on why you have air bubbles in your pool for more.
What Causes Pool Foam?
Pool water balance is essential for proper pool maintenance. Imbalanced chemicals in a pool can cause algae and foam. Too many chemicals in a pool with a lot of phosphates may also cause foaming.
Pool foam isn’t inherently dangerous or unsafe. In fact, it can be perfectly safe to swim in a pool with foam as long as your chemicals are correctly balanced. However, I still recommend getting rid of the foam as soon as you can so you have crystal clear, not “thick,” water.
Swimmers in Your Pool
Swimmers in your pool may cause foam. Swimsuits with lingering washing detergent may cause pool foam. Also, anything that the human body can shed or expel can cause foaming issues.
There are a few different things that can cause pool foam, including:
- Hair and skin products
- Pool chemicals
- Detergent from swimsuits
- Organic matter like sweat, saliva, body fat, and urine
It’s always recommended that one rinse off before swimming to remove any detergents, oils, shampoos, or makeup. Any of these contaminants can mix with the chemicals in your pool and cause foam.
That’s why public pools ask people to shower before entering—to rinse off the natural oils produced by our skin and hair. That’s also why chlorine gets added to the water—it helps maintain the pool by fighting against germs and protecting the health of all swimmers.
Total Dissolved Solids (TDS)
Foaming in a pool means there are high levels of total dissolved solids (TDS) in the water. TDS is the measure of solid matter that has liquefied. Foreign solids like oil, soil, and dirt dissolve in pools. High levels of TDS make pool water look cloudy and can even make it taste salty.
Swimming in pools with high TDS levels is not healthy and makes a pool harder to maintain, leading to a very dangerous environment. Pool operators have to maintain low levels of TDS to have a clear, healthy pool.
One of the most effective ways to get rid of foaming and maintain low TDS levels is to drain and refill the pool with fresh water. There is no specific schedule you have to drain and refill your pool on—you should just follow the reading on your TDS meter.
You just have to record the number on the TDS meter once you’ve refilled the pool and then drain it again once it reaches 1000 ppm over the original number you recorded. De-foaming products may help remove foam caused by skin and hair products, but they don’t work on foam caused by high TDS levels.
Newly Added Chemicals
While chemicals are vital for correct pool maintenance, they can also cause foaming issues, especially if you’ve recently added chemicals to your pool. It depends on the chemical, but algaecide tends to make pool water foamy.
We recommend investing in a quality algaecide—one without copper or other unnecessary metallics. Cheap algaecides contain metals that can cause pool foam. Additionally, always be careful with how much algaecide you’re using.
Make sure you follow the suggested doses per bottle instructions, as too much algaecide can also cause foaming. Spring pool opening kits may also cause pool foam. When a pool is first opened at the beginning of the season, there are no algae for the algaecide to kill, so the water becomes agitated and frothy.
We recommend using high-quality chemicals since low-quality chemicals can cause problems, including foaming. It’s important to ensure you balance all chemicals, especially alkalinity, calcium hardness, chlorine, and pH balance.
Foam caused by algaecide should break down on its own, but you can always skim your pool’s surface if you’d like to speed up the process.
Imbalanced Pool Chemicals
Your pool may have foam if it’s imbalanced. Remember to test your pool water using a pool test kit, especially to check your calcium hardness levels. Low calcium hardness means your pool water is soft, and soft water is prone to foam. I recommend adding calcium chloride to raise the levels and prevent foam if your pool has low calcium hardness.
Low calcium levels are the second most common cause of pool foam. Besides foaming, low calcium also causes scaling on a pool’s metallic components or in plaster pools. Your pool’s calcium hardness should be between 100 – 400 ppm.
You also have to be careful when trying to raise your pool’s calcium hardness, though. If it gets too high, you must dilute your pool’s water, which becomes very tedious. Balance is key, so make sure you’re always following the recommended doses and upkeep instructions.
If your pool water is imbalanced and you have to make adjustments, I recommend measuring the pH, calcium hardness, and total chlorine and then adjusting them separately in that order. Then leave your pool pump running for at least 24 hours to remove the foam.
Using aeration equipment in biguanide-treated pools may also cause foaming, although it should subside on its own after a few moments. Biguanide is used to sanitize pools as an alternative to bromine or chlorine. It works well but requires more frequent filter cleanings.
How to Treat Pool Foam
If you’ve run through all the previous causes and instructions and still find your pool has foam in it, there are still a few tricks to try. To successfully combat foam, I recommend following the instructions below.
The first thing I recommend for getting rid of pool foam is to use a hand skimmer. It can get rid of most of the foam right away, and with balanced pool water, the rest of the foam should quickly clear up.
As I mentioned, algaecide may cause foaming, but there are non-foaming algaecides available. It’s also best to avoid 10% polymer and copper-based algaecide because they can cause foaming or stain your pool due to their metal content.
I like this algaecide from BioGuard since it's copper-free, which should help prevent your swimming pool from turning a nasty green color.
If your pool’s chemicals are balanced, you can try shocking your pool with chlorine and then leaving its pump running until the foam fades.
When you shock a pool, you add chlorine to the water to sanitize it. This process gets rid of contaminants, bacteria, and cloudy water. It also prevents ammonia and living organisms, like algae, from dominating your pool.
In The Swim has a reliable cal hypo shock that is effective and easy to use.
The final step I recommend for ridding your pool of foam is adding anti-foam chemicals. Anti-foaming chemicals are designed and concentrated on getting rid of pool foam without interfering with the other chemicals in your pool.
If you’ve tried all these solutions and are still experiencing foam in your pool, you can always call an expert to come out and assess the situation. They might be able to pinpoint a solution for you better and help you eradicate the foam from your pool once and for all.
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Preventing Pool Foam
Prevention is always easier than trying to find a fix after the fact! I recommend that all swimmers take a light shower to remove cosmetics such as hair spray, deodorant, soap, body lotion, shampoo, oil, makeup, and laundry detergent before swimming in your pool.
Pool foam looks gross and can seem like a handful to deal with, but as long as you know what to look for, it takes no time at all to get rid of pool foam. Keeping your pool chemically balanced is a sure-fire way to make sure you never have to deal with that pesky foam ever again.
Have questions? Shoot me a note, always happy to help.