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How to Get Rid of White Mold in a Hot Tub

By Matt Giovanisci | Updated: January 5, 2017

Are you seeing a white substance forming on the surfaces of your hot tub and maybe even in the water itself? If so, there’s a good chance that you have white water mold growing in your hot tub.

Don’t worry, it’s a common problem, but one you need to solve as quickly as possible. First, let’s talk about what white mold in your hot tub and what causes it. Then, we will move on to treatment and prevention.

What Is White Mold in a Hot Tub?

It always helps to understand what you are dealing with, so first I want to discuss what it is and how it ended up in your hot tub. White water mold in a hot tub is not algae, although some may tell you otherwise. It’s actually a naturally occurring fungus. While it causes some of the same problems in your tub, water mold is more animal than vegetable.

Because it’s naturally occurring, it is a problem that all hot tub owners must be aware of. If let your hot tub go without thorough cleanings and regular water checks, this mold could begin to grow and flourish in your hot tub. Once you get it, it can be tough to get rid of it. However, if you do things right, you should be able to get rid of it once and for all.

Getting Rid of White Water Mold

If you find yourself with a white water mold problem, you are going to have a little work ahead of you. Whatever you do, don’t wait. The longer you let the mold grow the harder it will be to get rid of it for good.

  1. Drain your hot tub.
  2. Use a hot tub cleaner to clean all the surfaces of your hot tub and focus on areas where you can see the mold.
  3. Remove the filter and chemically clean it, don’t just rinse it. If it is more than a year old, throw it out and replace it with a new one.
  4. Refill the hot tub with fresh water using a hose filter.
  5. Shock the hot tub with a triple or quadruple dose of shock.
  6. After the shock has done its job, drain the hot tub again and refill it.
  7. Repeat the shocking process with a normal amount of shock.
  8. Test the water and balance it.

Once you have finished this process, regularly test your water and watch for anymore growth of this fungus. If you see any at all, repeat the process above.

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Prevention Is Key

As I said, once you get white water mold, it is a pain to get rid of. If you took the time to read the steps to get rid of it you know what I mean. The key to white water mold is prevention. If you properly maintain your hot tub and regularly test the water, then you shouldn’t have any problem. Here’s what you need to do:

  1. Once a week, clean all the surfaces of your hot tub with a scrub brush.
  2. Check your water quality and regularly add chemicals to oxidize any contaminants present in your hot tub’s water.
  3. If possible, expose your hot tub to the sun. The sunlight will help kill mold as UV light acts as a natural oxidizer.
  4. Every month, remove your filter and chemically clean it. If it is getting old, make sure you go ahead and replace it with a new one.
  5. Clean anything you put in your hot tub regularly such as hot tub toys or floats.
  6. After heavy bathing loads make sure you shock your hot tub to clean the water.
  7. Add spa shock on a regular basis to maintain optimum water quality and regularly test the pH, Total Alkalinity and Calcium Hardness in your hot tub.
  8. Run the hot tub at least six hours a day in order to ensure that all the water is properly filtered and cleaned each day.
  9. Periodically drain your hot tub and clean all the surfaces of your hot tub.
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If you make these maintenance tasks regular parts of your days and weeks, you probably won’t ever have to worry about white water mold again. White water mold doesn’t fair to well against a hot tub that is properly maintained. So remember, prevention is the key to stopping white water mold in its tracks.

Final Thoughts

Let’s be honest, white water mold is gross, and no one wants to have to deal with it in their hot tubs. Still, it is a common problem and one that is growing as more and more people bring hot tubs home to enjoy. If you are a new hot tub owner, I cannot stress enough how important proper maintenance is to a healthy hot tub.

If you don’t maintain your water, white water mold and other contaminants can flourish in your hot tub. Over time, this can lead to a nasty contamination that is hard to get rid of without a lot of hard work on your part. However, if you properly maintain your hot tub, you shouldn’t have anything to worry about.

If you do end up with white water mold, don’t worry. You will be able to get rid of it, but it will take work. Once you do clean out your hot tub, remember to keep the water properly maintained and clean so you won’t have to worry about it ever again.

Happy Soaking!

Matt Giovanisci is the founder of Swim University® and has been in the pool and spa industry since 1995. Since then, his mission is to make pool and hot tub care easy for everyone. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
A Cheat Sheet For Balanced Hot Tub Water and Crystal Clear Soaking.
Download this FREE printable cheat sheet to keep your hot tub clean and clear. You’ll never worry about your hot tub again with this easy-to-use guide.
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