Hot Tub Scum Be Gone: A Guide to Crystal Clear Water

hot tub technician cleaning hot tub scum
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If you're a hot tub enthusiast, you know nothing ruins a relaxing soak faster than a layer of scummy buildup on the water's surface. But what exactly is hot tub scum, and why does it form?

Hot tub scum combines various substances such as oils, lotions, bacteria, and other organic matter that can accumulate in your hot tub over time. But fear not! With some knowledge and some simple steps, you can keep your hot tub water sparkling and scum-free for a relaxing soak every time.

This guide will take a closer look at what hot tub scum is, what causes it, and how to prevent and remove it. We'll cover everything from maintenance tips and chemical treatments to physical removal techniques and when to call in the professionals.

Whether a seasoned hot tub owner or a beginner, you'll find helpful information and tips to keep your hot tub water crystal clear and scum-free. We'll also answer common questions about hot tub scum, so you can know that your hot tub is clean and safe for you and your family to enjoy.

So sit back, relax, and let's get started!

hot tub scum on hot tub

Understanding Hot Tub Scum & What Causes It

If you've ever experienced hot tub scum, you know how unsightly and unpleasant it can be. The accumulation of substances on the water's surface can make your hot tub look dirty and uninviting and even pose a health hazard.

There are several culprits behind hot tub scum, and understanding them is crucial for effectively preventing and removing the buildup.

In this section of our guide, we'll look closely at the top causes of hot tub scum, including human body oils and skin, personal care products, poor water chemistry, dirt, debris, organic matter, and metals in the water.

Let's dive into these causes and learn how to combat them for a crystal-clear hot tub.

  1. Human body oils and skin: When we soak in a hot tub, our skin's natural oils and dead skin cells can end up in the water, causing a buildup of scum on the water's surface. While avoiding bringing some of these oils and skin cells into the hot tub is impossible, showering before getting in can help reduce buildup.
  2. Personal care products: Many of us use personal care products like lotions, shampoos, and soaps throughout the day. Unfortunately, these products can mix with water and contribute to scum buildup. To prevent this, consider showering before entering the hot tub and waiting a few hours after applying personal care products.
  3. Poor water chemistry: The chemical balance of your hot tub's water is crucial for keeping it clean and free of scum. If the water chemistry is off, it can lead to scum buildup. Be sure to test the water regularly and adjust the chemicals as needed.
  4. Dirt, debris, and organic matter: Some dirt and debris will inevitably end up in your hot tub, especially if it's located outdoors. Leaves, bugs, and other organic matter can also contribute to scum buildup. Skimming the water regularly and vacuuming the bottom of the hot tub can help prevent scum from forming.
  5. Metals in the water: If your hot tub water contains high levels of metals such as copper and iron, it can contribute to scum buildup. These metals can oxidize and create a film on the water's surface. To prevent this, test your water for metal levels and use a metal sequestrant to prevent the metals from oxidizing.

hot tub dirt devris mold

Types of Scum

Hot tub scum can come in different colors and forms, and it can be frustrating to deal with. Understanding the different types of hot tub scum and what causes them can help you prevent them from forming in the first place. There are three common types of hot tub scum: blue-green scum, green scum, and brown scum.

  1. Blue-green scum: This is the most common type of hot tub scum and is often caused by a buildup of organic contaminants from human use and personal care products. To prevent blue-green scum, shower before entering the hot tub and avoid using personal care products in the tub. Maintaining proper water chemistry levels is also essential by regularly checking and balancing pH, alkalinity, and sanitizer levels.
  2. Brown scum: Typically caused by high pH levels in the hot tub water. When the pH levels are too high, it can cause the water to become cloudy and create a brownish film on the water's surface. To prevent brown scum from forming, regularly test the hot tub water's pH levels and adjust them as needed using chemicals like pH decreases and increasers.
  3. Green scum: Often caused by a buildup of metals in the water, such as copper or iron. To prevent green scum, regularly test the water for metal levels and use a metal sequestering agent to keep them in solution. You can also use a hot tub water clarifier to help filter out any metals that may be present in the water. It's also important to maintain proper water chemistry levels to prevent metals from becoming insoluble and settling on the bottom of the hot tub.

preventing hot tub scum

How to prevent hot tub scum

Keeping your hot tub water clean and scum-free is easier when you take preventative measures. Here are the top ways to prevent hot tub scum buildup:

  1. Shower before entering the hot tub: This will help remove oils, dirt, and personal care products from your skin, preventing them from accumulating in the hot tub water.
  2. Clean your hot tub filter regularly: Your filter is responsible for trapping impurities in the water and keeping your hot tub water clean. By cleaning your hot tub filter regularly, you can help ensure it is functioning at optimal levels.
  3. Shock your hot tub: Shocking the water helps destroy organic contaminants and other bacteria that can lead to scum formation. Make sure to always have a good shock option in your hot tub chemical bag.
  4. Keep your hot tub covered when not in use: The perfect fitting hot tub cover can help prevent dirt, debris, and other impurities from entering the water, reducing the chances of scum formation.
  5. Drain and clean your hot tub every three months: This ensures that all the water and impurities are removed from the hot tub, preventing the buildup of scum and other contaminants. Use a hot tub cleaner and a microfiber hot tub cleaning towel.

Following these preventative measures can help prevent hot tub scum buildup and keep your hot tub water clean and inviting.

remove hot tub scum

How to remove hot tub scum

If you've already noticed some scum buildup in your hot tub, don't worry! There are several methods and hot tub accessories to help remove it and clear your hot tub water. Here are the top ways to remove hot tub scum:

  1. Use a microfiber hot tub cleaning towel: These yacht quality cleaning towels are crafted with a unique microfiber blend enhanced with waffle grooves that trap your hot tub's scum and grime, just like waffles capture syrup and butter.
  2. Use a scum absorber: Hot tub scum absorbers are oil-absorbing sponges that float on the water's surface and help remove oils and other impurities that can cause scum buildup.
  3. Use an Enzyme cleaner: A hot tub enzyme cleaner is a specially formulated chemical designed to break down and eliminate scum buildup. Follow the manufacturer's instructions carefully when using this product.
  4. Clean or replace your filter: If it is clogged or not functioning properly, it can contribute to scum buildup. Cleaning or replacing the filter can help ensure it is working efficiently.
  5. Fully drain your hot tub: If all else fails, draining and fully cleaning your hot tub can help eliminate scum buildup and other contaminants. Follow the manufacturer's instructions, or use a hot tub cleaner for the best results.

Using one or more methods, you can remove scum buildup in your hot tub and keep your water clean and inviting.

clean hot tub water

What if the scum won't go away?

If the scum in your hot tub won't seem to disappear, it may be a sign that you have other issues in your hot tub.

One potential cause could be calcium scale, a buildup of calcium deposits caused by high calcium levels in your water, or an unbalanced pH.

Mold or mildew can also be a culprit, particularly if your hot tub cover is not properly ventilated.

Finally, if the scum in your hot tub has a green tint, it may indicate an algae bloom. If you suspect any of these issues, it's important to take action quickly to address them and get your hot tub back to a clean, safe state.

If you've tried various methods to remove scum from your hot tub and it won't go away, it might be time to consult a professional. A hot tub professional can help you determine the underlying cause of the scum and identify any other issues that may be affecting the health and cleanliness of your hot tub. They can also guide how to maintain your hot tub to prevent future scum buildup properly.

Don't hesitate to contact a professional for help if you're struggling to keep your hot tub clean and scum-free.


We hope this guide has helped you understand what hot tub scum is and how to prevent and remove it.

Hot tubs are a fantastic way to relax and unwind, but they require proper maintenance to keep them clean and healthy. By taking simple preventative measures like showering before entering your hot tub, regularly cleaning your filter, and maintaining good water chemistry, you can keep scum at bay and enjoy crystal-clear water in your hot tub.

And if you encounter stubborn scum buildup, don't hesitate to consult a professional to help you identify the underlying cause and provide guidance on maintaining your hot tub for optimal health and cleanliness.

With the right knowledge and maintenance, you can enjoy a hot tub that's both relaxing and hygienic.