Why Do I Foam In My Hot Tub?

January 15, 2024

Spa,Hot,Tub,Water,Bubbles,CloseupIf you own a hot tub, you may have experienced the frustrating issue of foam forming on the water’s surface. Foam in a hot tub not only looks unsightly but can also be a sign of a more significant underlying problem. In this blog post, we will explore the reasons why foam may appear in your hot tub and discuss ways to prevent and resolve this issue effectively.

1. Residual Soaps and Detergents:

One of the common culprits for foam in a hot tub is residual soaps and detergents. When you or your guests enter the hot tub without properly rinsing off soap or shampoo, it can mix with the water and create foam. Additionally, if you use certain cleaning products to clean the tub, remnants of these products can also contribute to foaming.

To prevent foaming caused by soap and detergent residues, ensure that everyone thoroughly rinses themselves before entering the hot tub. Avoid using regular soaps or cleaning agents on hot tub surfaces, as they can leave residues that contribute to foam formation. Instead, use hot tub-specific cleaning products that are designed to be residue-free.

2. Body Oils and Lotions:

Another common cause of hot tub foam is body oils and lotions. These substances can be easily transferred from your skin into the water, where they accumulate and create a foam-like substance. Sunscreen and other body care products can also contribute to foam in your hot tub.

To prevent excessive body oils and lotions from causing foam, encourage bathers to shower before entering the hot tub. This practice can help remove any oils and lotions from the skin, reducing the amount that enters the water. Additionally, consider using a hot tub defoamer product, specifically designed to break down and eliminate foam caused by body oils and lotions.

3. Alkalinity and pH Imbalance:

Imbalances in the alkalinity and pH levels of your hot tub can also contribute to foam formation. High alkalinity or pH levels can create conditions that enhance the production of foam. Additionally, high levels of calcium in the water can cause foaming, known as “hardness foaming.”

To keep your hot tub water balanced and prevent foam caused by alkalinity and pH imbalance, regularly test and adjust the water chemistry. Keep the alkalinity levels between 80-120 parts per million (ppm) and the pH levels between 7.2-7.8. Use appropriate hot tub chemicals to adjust the levels as needed and help maintain a properly balanced environment.

4. Dirty or Overused Filters:

Dirty or overused filters can contribute to foam in your hot tub. When filters are clogged with debris and contaminants, they become less effective at capturing particles, leading to excessive foaming. Additionally, old or worn-out filters may not be able to handle the demands of keeping the water clean, resulting in foamy water.

To prevent foam caused by dirty or overused filters, make sure to regularly clean and maintain your hot tub filters. Follow the manufacturer’s instructions on how often to clean or replace the filters. Depending on usage and the quality of your water, filters may need to be cleaned or replaced every few months.

5. High Dissolved Solids:

High levels of dissolved solids in the water can also contribute to hot tub foam. These solids, including minerals, metals, and other residues, can accumulate over time and promote foam production. This issue is particularly common in areas with hard water.

To combat foaming caused by high dissolved solids, use a hot tub clarifier product. This product helps bind suspended particles together, making them easier to filter out of the water. Regularly shock your hot tub to break down organic compounds and remove any lingering particles.


Foam in your hot tub can be caused by various factors, including residual soaps and detergents, body oils and lotions, alkalinity and pH imbalance, dirty or overused filters, and high dissolved solids. By taking preventive measures such as rinsing before entering the hot tub, using appropriate cleaning products, maintaining proper water chemistry, regularly cleaning or replacing filters, and using clarifiers and shock treatments, you can effectively prevent and resolve foam in your hot tub. Remember to refer to your hot tub manufacturer’s guidelines and seek professional help if the foaming issue persists despite your efforts.

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Family owned and operated since 1959, Alcoe located in Lubbock, TX has been providing five decades of superior experience and knowledge which makes us uniquely qualified to understand and fulfill the expectations of each of our clients. We specialize in the sales, install and service of spas/hot tubs, swim spas, sun-rooms, saunas, infra-red grills, outdoor fire pits and MORE! Round up your swimsuit, towel and goggles, then come experience swimming and relaxing in an Alcoe swim spa first hand. Contact us today to learn more about what we can do for you!

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