9 Reasons Your Hot Tub is Foaming (and How to Fix it!)

Maintaining clear water in hot tubs is essential for keeping hot tubs functioning properly, as well as safe to soak in. When hot tubs become cloudy or foamy, it may be an indicator that something is wrong with your hot tub water chemistry. If you are wondering why your hot tub is suddenly foaming, you have come to the right place. Today, we’ll cover the 9 reasons your hot tub is foaming and solutions for fixing them.

Common reasons for foaming water in hot tubs include these 9 problems:

  • Low calcium levels
  • Unbalanced water
  • Too many chemicals
  • Inferior chemicals
  • Hair and skin products released in the hot tub
  • Laundry detergent on swimwear
  • Debris in the water
  • High usage
  • The hot tub needs draining and refilling

If you’re looking for the solutions for these 9 common hot tub issues, you have come to the right place! Below, we’ll take a look at why hot tub water is foamy, and how to solve it.

1. Low Calcium Levels

One reason for foaming water in hot tubs is a low calcium level. This is primarily caused by water hardness, which determines how hard or soft your hot tub water is. When hot tub water becomes too soft, it not only makes your hot tub appear foamy, but it may ultimately damage the hot tub’s equipment.

Before you add calcium to your hot tub water, it’s important to understand how calcium hardness works. Similar to the pH and alkalinity levels of your hot tub, calcium hardness must be balanced. If it is too low, the water will become corrosive. If calcium levels are too high, however, the water will become cloudy and may clog your filters.

Before adjusting your calcium levels, measure your Total Alkalinity to make sure it’s balanced. Many issues can occur when Total Alkalinity and pH are off-balance. If the Total Alkalinity and pH levels appear normal, it is likely your hot tub’s calcium levels that need adjusting.

How to Fix Low Calcium Levels

Hot tub water should be checked typically once a week using test strips. These test strips will indicate whether or not your hot tub has low calcium hardness. Ideally, the range for calcium hardness in hot tubs should be 150-250 ppm (parts per million).

If your hot tub’s calcium level is lower than the ideal range, you will need to manually raise the calcium hardness. This can be done by adding a calcium hardness booster such as calcium chloride into your hot tub.

2. Unbalanced Hot Tub Water

Similar to low calcium levels, unbalanced water can create a number of issues in hot tubs, including foaming water. If your hot tub is appearing foamy or cloudy, it may be a sign your hot tub’s water chemistry is out of balance.

In addition to making water foamy, unbalanced hot tub water may emit a foul odor, as well as cause water to appear green. This not only gives your hot tub an unsightly appearance, but it makes the water unsafe to soak in.

How to Fix Unbalanced Hot Tub Water

Before you can fix unbalanced hot tub water, you must first find what’s causing the issue. Every week, test your hot tub’s water with test strips. Test strips will determine the water’s pH, Alkalinity, and sanitizer levels, all of which are important for maintaining balanced hot tub water.

If pH levels are unbalanced, you may need to add more chemicals to either raise or lower the pH levels in your hot tub. Another way to balance out the pH levels in your hot tub is by adding new water. This, in turn, will get rid of any foam appearing in your hot tub.

3. Too Many Chemicals

Chemicals are an essential part of hot tub maintenance. With that being said, too many chemicals can damage the filtration system, which may lead to foaming water in hot tubs.

In addition to making water foamy, a mixture of too many chemicals can make hot tubs comfortable to sit in. Large chemical doses can irritate people’s eyes and skin, making the water uncomfortable to soak in.

How to Balance Chemicals in Your Hot Tub

Every 3 to 4 days, check your water’s chemical levels with a test strip. When adding chemicals, add one chemical at a time and wait approximately two hours before adding the next chemical. Additionally, make sure the pump is turned on in your hot tub so that the chemicals are properly distributed throughout the water.

Once a week, it is recommended to shock your hot tub. Be careful not to overdose the chemicals in your hot tub, as this can create foam in your water. Always carefully measure your shock dosage before putting it in the water.

4. Using Inferior Chemicals

Because hot tubs can be expensive to maintain, many hot tub owners choose to use cheaper chemicals. While this may lower your maintenance costs, it can also cause issues in your hot tub water, such as foaming.

There is a reason why inferior chemicals are cheaper to buy than high-quality chemicals. Although it may appear that any chemical will do the job, inferior chemicals lack the ingredients to keep hot tub water clean. This is primarily because inferior chemicals contain fewer active ingredients and more fillers. As a result, you may end up adding more chemicals than you need just to keep the hot tub water clear.

How to Buy High-Quality Chemicals

The solution to this common issue is very simple: Only purchase high-quality chemicals for your hot tub. Make sure the chemicals are produced by a trusted source. Although these chemicals are more expensive, they are well worth the extra dollars, as they ensure your hot tub will continue functioning properly.

5. Hair and Skin Products in Hot Tub Water

If your hot tub begins foaming as soon as you enter the water, it could be caused by hair and skin products. Products such as deodorants, lotions, colognes, oils, perfumes, and shampoo will mix with the water in hot tubs, creating a foamy or even cloudy appearance.

How to Prevent Foamy Water Caused by Hair and Skin Products

There is a reason why public hot tubs and pools display signs that ask individuals to shower before entering the water. Because hair and skin products can lead to foamy water, taking a shower prior to entering the hot tub will wash these products off your skin. Additionally, taking a quick shower will wash off any dirt and sweat on your body, which may also cause foamy and cloudy water.

If you aren’t wearing any skin or hair products, you may enter a hot tub without taking a shower first. However, it is still a good idea to take a quick shower to rinse off any dust or dirt on your body.

6. Laundry Detergent on Swimwear

If your hot tub’s water appears foamy even after taking a shower, it may be because your bathing suit has laundry detergent or fabric softener in it. This is particularly true if you’ve recently washed your swimwear with detergent.

How to Prevent Foamy Water Caused by Laundry Detergent

If your bathing suit has laundry detergent in it, make sure to thoroughly rinse it before entering your hot tub. Only use fresh, clean water to rinse your bathing suits.

Another option is to not use laundry detergents on your bathing clothes. In fact, it is recommended not to use detergent on bathing suits, as it may wear out the fabric. If you do choose to use detergent, make sure it is a mild laundry detergent. Avoid using fabric softener, and rinse your swimwear before entering the hot tub.

7. Debris in the Water

If you often take your cover off the hot tub, you may experience foamy water caused by the debris. As debris enters the hot tub, it may clog the filter, resulting in cloudy, foamy water.

How to Remove Debris in the Water

Make sure your filter is properly working to avoid debris polluting the water. If the filter becomes clogged, you may need to remove the debris by hand to prevent water from becoming foamy.

Additionally, make sure your hot tub’s cover is secured to the hot tub. The cover will eliminate falling leaves and other debris from entering the hot tub when not in use.

8. High Hot Tub Usage

Simply put, the more people enter your hot tub, the greater the chance your hot tub water will become foamy. Because many people may be wearing skin and hair products, your hot tub is prone to become foamy when it experiences high usage.

How to Fix Foamy Water from High Usage

If your hot tub is experiencing high usage, it is best to keep your filter running often and chemicals properly balanced. Depending on the number of people in your hot tub, you may need to add more chemicals than usual, as long as you’re careful not to overdose.

Additionally, you may ask all individuals to shower before entering the hot tub. Because many people will likely be wearing skin and hair products, it is best to have them rinse off before taking a soak in the hot tub.

9. The Hot Tub Needs Draining

When hot tubs begin foaming, it may be a sign it’s time to drain and refill the hot tub. Generally, hot tubs should be drained and refilled every 3 to 4 months. If your hot tub is highly used, you may need to drain it more often than this.

Draining and Refilling Your Hot Tub

To drain your hot tub, first, turn off all power to your hot tub. Next, use either a spigot or submersible pump to drain the hot tub. If using the drainage spigot, you’ll need to attach a hose to the spigot and open the spigot’s ball valve. For submersible pumps, simply connect a hose to the pump and turn on the pump’s power switch.

Once a hot tub is drained, you’ll want to clean the inside of it. Use a soft, damp rag to gently clean the hot tub’s interior, and avoid using harsh chemicals. You may also clean the filter by soaking it in a degreaser and rinsing it with a garden hose.

After you’ve cleaned the hot tub, you may refill it using a garden hose. To prevent airlocks from occurring, you may need to fill the hot tub at the fill pipe rather than placing the hose directly into the hot tub’s interior shell. 

Draining and refilling your hot tub should get rid of any foaming or cloudy water. Make sure to keep the water chemistry balanced after refilling the hot tub, as foaming water may occur when chemicals and pH are off-balance.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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