How to Remove and Prevent Hot Tub Stains

by Matt Giovanisci | Last Updated: January 7, 2016

Does your hot tub ever have that, not so fresh, feeling? We’ve all been there. Trust me it is just a part of life.

Stains that form on the shell of your hot tub or on the fixtures not only look gross, they can also damage your hot tub if you don’t deal with them right away. If your hot tub has stains on the sides there are things you can do to get rid of them once and for all and there are even steps you can take to prevent them from ever forming in the first place.

Let’s examine some of the most common stains and what you need to do to clean them from your spa so you and your guests can enjoy a clean and clear hot tub.

Typical Types of Stains

There are many different types of stains that can form on your hot tub. Most are relatively easy to get rid of but all them I have to admit look rather gross on the sides of your hot tub. Some of the most common stains you will see are:

While all of these stains may seem very different, they can all be cleaned with many of the same chemicals and using the same process. Let’s take a look at exactly how you remove those stains once and for all.

Remove Those Stains

Unfortunately, there is no magic formula I can give you that will remove those stains automatically. You are going to have to drain that hot tub and put in a little good old-fashioned elbow grease to get rid of them.

Still, there are many different chemical hot tub cleaners that you can use along with a nice soft cloth or sponge that will help you cut through those stains and return your hot tub to that bright finish you have come to expect.

To remove the stains, follow these easy instructions.

  1. Power off your hot tub. Consider turning off the power at the breaker if necessary.
  2. Drain the water from your hot tub.
  3. Dry the shell of your hot tub to remove the excess water left over after draining.
  4. Apply the cleaning chemicals to your hot tub following the instructions on the package.
  5. Using a little elbow grease, scrub the sides of your hot tub thoroughly.
  6. Rinse the hot tub and allow it to dry.
  7. Refill the hot tub.
  8. Balance your water.

Once you have completed all these instructions, your hot tub should be ready for you to enjoy again stain free. Of course, you will want to do your best to stop those stains from forming again on your spa.

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Prevent Stains From Returning

So how do you stop the stains from forming? I can sum it up in two words for you – water chemistry. That’s right. If you have the proper chemical balance in your hot tub’s water, then stains will never have a chance to form. Now, this doesn’t mean that you won’t have to drain your hot tub periodically and give the shell a good cleaning. Nothing will ever free you from that. But it does mean that those hideous (and sometimes gross) stains that can form on the side will go away.

Add Sanitizer

To balance your water properly, first, you need to make sure you add the proper amount of sanitizer to your hot tub. Refer to your hot tub’s manual to see how much you need to add based on the amount of water in the hot tub.

Total Alkalinity and pH

Next, it is time to test the total alkalinity (TA) and pH. Always balance the TA first as that will usually bring the pH into balance at the same time. Still, you may have to readjust your water’s pH even after you have balanced the alkalinity.

Water Hardness

Once you have brought your water into proper balance, it is time to measure the hardness of the water. The hardness is the amount of calcium dissolved in the water. If there is too much calcium, the water will be hard and could leave a scale buildup type of stain on your hot tub. If it is too low, you could get corrosion on your hot tub’s shell or even the jets.

Now that all of this is complete, it is time to add stain and scale prevention to your spa. This will help prevent the buildup of some of the most common stains you will find in your hot tub and make it much easier for you to clean it later.


Hey, no one wants to take a soak in a dirty hot tub, and there is nothing worse than looking at a hot tub with unsightly stains on the side. While they may be harmless, they are still kind of gross. Admit it, you know I’m right. Luckily, you can easily remove those stains with the right materials and a little elbow grease and the proper water balance can help you prevent them from ever forming again.

Now that you know what you have to do, all you have to do is do it. Get in there and drain your hot tub and give it the cleaning it deserves and then work on your water so you never have to worry about those terrible stains again.

Happy Soaking!

Matt Giovanisci, the founder of Swim University®, started in the pool and spa industry at age 13 and moved to bigger companies along the way, helping thousands of pool and hot tub owners every year. He wanted to share his knowledge and unique teaching style on a larger scale, so he launched Swim University® in 2007. Since then, he's worked to make pool and hot tub care easy for over 10 million homeowners. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.

Learn How to Keep Your Hot Tub Clean and Clear All Year Long

You'll save $100 right away with this easy-to-follow digital ebook and video course. This is the guide that hot tub manufacturer doesn’t provide you.

Click here to learn more
The Hot Tub Handbook