3 Quick and Easy Ways to Remove Hot Tub Foam for Good

Foam can build up in your tub for a variety of reasons, but with the right techniques and products, it is easy to get rid of the foam and return your hot tub to its crystal clear state. Let’s first take a quick look at how.

The 3 ways to get rid of hot tub foam are by using a chemical-based foam remover; by draining, cleaning, and refilling the hot tub with fresh water; and by using a combination of vinegar and baking soda to treat the affected water. Depending on your chosen method, removal will take between 15 minutes and 36 hours.

In this article, you’ll learn:

  • The causes of hot tub foam
  • If it’s safe to use a spa with foam
  • How to remove foam in just 15 minutes
  • How to get rid of foam and make sure it doesn’t come back

The Causes of Hot Tub Foam: Understanding the Root of the Problem

For foam to appear in your hot tub, it needs three things: water, air, and surfactants. Surfactants are sticky molecules that reduce the surface tension of a liquid, making it easier for substances like oil and water to mix.

Because the surfactants often create a thin layer of water between themselves, they tend to push the water molecule into a ball, thereby forming a bubble. The more surfactants you have, the more stacking you get, and the more bubbles form, which then leads to hot tub foam.

The main surfactants that cause hot tub water to foam include:

Personal care products

Products like shampoo, conditioner, moisturizers, hairspray, perfumes, deodorants, and makeup contain oils and other ingredients that shouldn’t mix with your spa water. They can make your sanitizers work overtime, rendering them ineffective.

Residual soap or phosphates from the laundry detergent used to wash your bathing suit also cause foam to build up. The more of these products you use, the more likely surfactants will build up in your hot tub.

Food and drink

Spilling drinks or food in your hot tub results in a chemical imbalance (e.g. overly high or low pH levels) that causes foam to appear. Therefore, ensure you keep alcoholic drinks, beverages, and food away from the hot tub.

Human bodies

The human body is full of natural oils, dead skin cells, and sweat that can affect your water chemistry. If your sanitizing agents are overburdened by these contaminants, you’re probably going to have a problem with foam in your hot tub.

Low calcium hardness

Low calcium hardness is found in soft water, and it decreases the surface tension in the water. This makes it easier for foam to form on the surface of the water. 

Hot Tub Foam: Is It Safe for You and Your Family?

Hot tub foam is not harmful to your health, but it can cause damage to your hot tub. Foam is caused by a chemical imbalance in the water. 

Foam should be removed as soon as possible to prevent corrosion of hot tub parts and discoloration of the hot tub shell walls. You want to avoid expensive repairs to the hot tub shell and any mechanical component.

No amount of foam is normal in a hot tub, and the foam will not go away on its own. Foamy hot tub water can happen from time to time and is something that can be easily managed.

If you fail to maintain your hot tub water properly, you will end up having a problem with too much foam. Bubbles that form in the hot tub while the jets are running should not build on one another.

Therefore, a single level of quick-dispersing bubbles on the water surface is normal. But bubbles that grow on top of each other and climb higher out of the water surface are not normal. 

If your spa keeps foaming up, it’s a sign that the water is too old or that there aren’t enough sanitizing chemicals in the water. Turning on the hot tub jets when the water is like this will cause the foam to appear on the surface of the water.

Foamy hot tub water can also be a sign that it is time to change the water. In addition, the foam can serve as an ideal transport medium for bacteria, carrying it to the surface where it can be more readily absorbed by bathers.

When you turn off the jets or air bubbler system, all bubbles left in the spa water should completely disperse within 60 seconds or less. If you have persistent foam that hangs around longer than a minute or so, there are ways you can improve your water quality to reduce the amount of foam in your hot tub.

Quick Fix: Eliminate Hot Tub Foam Without Draining

If you don’t have time to drain and refill your hot tub (it takes around 36 hours), you can get rid of the foam temporarily by using a foam removerOpens in a new tab. or anti-foam chemical. This type of chemical will eliminate the foam in your spa almost instantly (about 15 mins), and the effect lasts up to 24 hours.

However, it is important to note that defoamers are designed to temporarily break the bond between the water and the surfactants. They don’t address the cause of foam in your hot tub. Instead, they just relieve the problem for a little while. 

Therefore, you’ll need to clean the plumbing and fully drain all of the water in the hot tub to get rid of the foam for good. If you don’t, the foam will return once the anti-foam chemical has been used up.

How to Get Rid of Hot Tub Foam for Good

1. Test your water

Before you do anything corrective, test the hot tub water to find out the pH, alkalinity, and sanitizer levels. Also, check for total dissolved solids (TDS), as these are the surfactants. 

Note that low calcium hardness can cause foam in your hot tub. Low calcium can also cause other problems like corrosion and etching on your finishes. Therefore, it’s important to regularly test calcium hardness levels as well.

2. Drain and refill

If you’ve tried both methods and the hot tub is still full of foam, the best way to get rid of the foam is to drain the spa, clean it thoroughly and refill it with fresh water. At this time, you can add a chlorine shock treatment to reduce the chance of foam forming.

You will also need to carry out a full line flush of the hot tub’s plumbing. Even with correct sanitizer levels, a hot tub can develop biofilm, which is a breeding ground for bacteria. The only way to remove the biofilm build-up is by using a line flush cleaner like Ahh-Some

Add the line cleaner and allow it to run for some hours. As the water circulates, you’ll notice scum forming on the surface of the water. The scum means the cleaner is working well and clearing all the biofilm from the pipes. With that out the way, you can then move on to draining the hot tub.

Basic steps to drain your hot tub:

  • Remove the filters. Depending on how dirty the filters are, you can either clean them with a filter cleaner or replace them.
  • Turn off the power to your hot tub, disconnect anything electrical, and trip the breaker.
  • Drain the hot tub using a sump pump or the drain plug.

After draining the hot tub, you’ll need to clean it thoroughly. Here are basic steps to clean and refill your hot tub:

  • Once your hot tub is entirely drained, wipe down the interior surface with a mixture of one part white vinegar to four parts water. Or you can use a specialist hot tub cleaner.
  • Thoroughly rinse the inside of your hot tub and wipe it down.
  • Make sure to remove all traces of the cleaner. If you don’t, you’ll end up with foamy water again.
  • Replace the filters.
  • Refill the hot tub. It is advisable to use an inline hose pre-filter attached to your garden hose to prevent chemical impurities.

After draining, cleaning, and refilling the hot tub, you’ll need to test the water, add chemicals, and allow the water to circulate for at least 24 hours. When the circulation is complete, test the water again to ensure it’s ready for soaking.

2 Household Remedies for Removing Hot Tub Foam Naturally (No Drain)

1. Straight vinegar

Once you’ve tested your water and taken note of all the chemical levels, you can use vinegar to get rid of the foam. Vinegar works as a powerful defoaming agent. If there’s only a thin layer of foam in your spa, you can pour vinegar straight into the water. 

Apply the vinegar using a ratio of 10 to 1. For example, if the hot tub holds 100 gallons of water, use 10 gallons of vinegar. The downside is you may notice a slight hint of vinegar smell coming from the water, but this will evaporate over time.

2. Vinegar and baking soda

Rather than using vinegar alone, you can use a mixture of vinegar and baking soda. Mix a solution of vinegar and baking soda in a bucket, with one 1 part baking soda, two parts vinegar, and nine parts water. 

Although this combination will create an initial foam, the vinegar will help activate the baking soda. Pour the solution into the hot tub and let it work for at least 30 minutes. The solution will dissolve the dead skin cells and oils that caused the foam to form.

Eliminate Hot Tub Foam for Good With These Prevention Tips

  • Before entering the hot tub, shower to remove any body oils, dead skin, soap residue, beauty products, or deodorant. It doesn’t have to be a full shower. Just a quick rinse is enough.
  • Don’t wash your bathing suit in the washing machine. Instead, rinse it using hot water to avoid introducing laundry detergent into the hot tub.
  • Avoid putting your head under the water unless you’re sure your hair is free (or as free as possible) of shampoo, natural oils, styling products, conditioner, and other hair care products. If you have long hair, tie it up or wear a cap to keep it out of the water. This applies to beards too.
  • Do not eat or drink in the hot tub. This eliminates the chance of something spilling into the spa water.
  • Do not fill the hot tub with softened water. Use a calcium hardness increaser to raise the calcium levels if you live in a soft-water area.
  • Buy your chemicals from a trusted source. Don’t buy cheap chemicals. Investing in known brands will save you money in the long run.
  • Maintain a regular hot tub maintenance routine. This includes weekly or bi-weekly water testing and a full hot tub draining and cleaning every three to four months. Use water test strips and adjust chemicals accordingly.
  • Use spa shock every week to break down impurities and oxidize the water.
  • Open the hot tub cover at least once a week to introduce oxygen.

Neglecting your hot tub maintenance routine for a few days can lead to a build-up that will cause foamy water in your spa. 

Foam caused by low calcium water is of particular concern because it can lead to corrosion in the hot tub’s parts and fittings. This is because water that is starved of calcium tries to source the needed calcium from the metal components in your spa.

Use a calcium hardness increaser if the levels are low. Ensure you keep the hot tub covered because rain or snow can also lower calcium levels.

Joshua Milton

Joshua Milton is a seasoned hot tub enthusiast. With many years of experience in the industry, he offers valuable insights on hot tub maintenance, health benefits, and relaxation techniques.

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