How do you get rid of foam in a hot tub or swim spa? The fastest way is to use a Hot Tub Defoamer (Anti-Foam). This will quickly remove the foam so you can enjoy a soak. But it’s likely to come back and keep happening.
A quick relief to reduce foam in your hot tub. But not a complete remedy.
In order to solve constant hot tub foaming, you need to understand what causes it to prevent it. Here’s a simple guide on how to get rid of hot tub foam. You can watch the quick video below or keep reading for a complete hot tub foam tutorial.
Foam needs three things: water, air, and surfactants to appear. Surfactants are super-sticky molecules that reduce the surface tension, which makes it easier for substances like oil and water to mix. This makes the water viscous or “thick.” Think about adding cream to your coffee.
Your hot tub contains water and some surfactants, even if you properly maintain your hot tub chemistry. But if you slip a little on your maintenance schedule, you might flip on your jets and find yourself with a foamy mess. The more surfactants you have, the more bubbles (foam) you get.
The main foam-causing culprits in your hot tub are…
If your sanitizing agents are overburdened with body oil and dead proteins, you’re probably going to have a bubble bath instead of a hot tub.
Yes! You can buy test strips or a liquid test kit that tests for total dissolved solids (TDS). If you have a high TDS reading, you have high surfactants. However, this is not necessary to do if you drain and clean your hot tub every 3-4 months. Total dissolved solids are the result of “too much crap” in your water. That includes hot tub chemicals, oils, dead skin cells, etc.
While clearing a hot tub full of foam may seem like an impossible, messy task, it’s actually pretty simple.
Before you do anything corrective, test your spa water to find out what your pH and alkalinity water balance. And your current sanitizer levels (chlorine or bromine). Knowing what your water chemistry looks like after foaming can help you understand how to avoid the problem in the future.
Another thing to note is low calcium hardness levels may cause foam in your hot tub. Low calcium means you have soft water. It can cause other problems, too, like corrosion and etching on your finishes. So, it’s important to regularly test these levels as well.
Tests for 7 important chemistries in seconds: Total Hardness, Total Chlorine, Total Bromine, Free Chlorine, pH, Total Alkalinity, and Cyanuric Acid.
Once you’ve tested your water and made note of all the chemical levels, the best thing you can do to get rid of the foam is to drain and clean your hot tub. If you have enough surfactants in your water to cause foaming, you may also need to do a line flush and replace your filters.
Since you need to drain your hot tub anyway, this is the perfect time to perform a hot tub deep clean as well.
Basic Steps to Drain Your Hot Tub:
Basic Steps to Clean and Refill Your Hot Tub:
After you’ve drained, cleaned, and refilled your hot tub, test the water, add chemicals, and allow the water to circulate for at least a day. When the circulation is complete, test the water one more time to ensure it’s ready for soaking.
Our hot tub kit makes taking care of your water easy. It includes Hot Tub Weekly Cleanse, Detox, and Filter Cleanse to use every 3-4 months for deep cleaning.
Say you’ve got a party coming up and not enough time to go through all the steps to correct a foamy hot tub. You can buy a foam remover chemical, which will get rid of the foam in your hot tub almost instantly and can last for up to 24 hours.
Remember, foam remover chemicals do not address the cause of foam in your hot tub. It just relieves the problem for a little while. You’ll still need to drain and refill your hot tub to get rid of the foam for good.
A quick relief to reduce foam in your hot tub. But not a complete remedy.
I asked over 15,000 hot tub owners via email if they had any questions about getting rid of hot tub foams. These are the questions they asked, and here are my quick answers.
A little foam when jets are on is normal, but excessive foam indicates a water imbalance or contamination. It’s a sign to check your water chemistry.
Shocking can help if the foam is due to organic contaminants, but if it’s caused by soaps or oils, you might need to drain and refill your tub.
Foam will disappear if you correct the water imbalance or contamination causing it. Sometimes, a simple water change does the trick.
Not directly, but high pH can lead to imbalances that make foam more likely. Balanced water is less foamy water.
Baking soda won’t directly reduce foam. It’s used to raise alkalinity, which can indirectly help if low alkalinity is causing the foam.
Vinegar isn’t a go-to solution for hot tub foam. It’s more about balancing chemicals and cleaning out contaminants.
Use a defoamer as needed, but if you’re using it often, it’s time to check and correct your water chemistry.
Excess chlorine itself doesn’t usually cause foam. Foam is more often due to organic contaminants or imbalances in your water chemistry.
Matt is the founder of Swim University. He's been in the pool industry since 1993. His mission is to make pool care easy for everyone. Each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
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