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How To Clean Mold From Inflatable Hot Tubs In 7 Easy Steps

Updated January 10th, 2024

Relaxing in a hot tub feels great. Having an inflatable hot tub at home is a great affordable way to enjoy a hot tub. Regular cleaning and maintenance of your hot tub are essential to keep it enjoyable. No matter how good you do, sooner or later chances are you will find mold, algae, or mildew in your inflatable hot tub. When this happens, it’s time to clean your hot tub. Let’s look at how to clean mold from inflatable hot tubs in 7 easy steps and how to keep mold, algae, and mildew from coming back.

How To Clean Mold From Inflatable Hot Tubs In 7 Steps

If your hot tub is smelly, has funky colored water, has white, black stuff floating or growing in it, you’ve got a problem. You have mold, algae or mildew growing in it and possibly all 3. If your hot tub is suffering from these conditions, it’s time to take action. The steps to cleaning your hot tub are similar for all 3. If you have an issue with nasty stuff growing in your hot tub it’s time for a thorough cleaning of your hot tub and cover.

Step 1 – Figure out whether you have mold, mildew or algae in your hot tub

Mold, algea and mildew are 3 different organisms. They come from different problems with your hot tub. All 3 are signs of neglect and improper cleaning and chemical levels. How do you know which you have growing in your hot tub?


Mold is usually black or white. Mold is fungus that can grow on the surface or on the water itself. Mold will look like white or black patches growing on the hot tub surface or in the jets. It may also be white stuff floating on the water. Mold comes from lotions and soaps that people had on them when they got in your hot tub and it dissolved into the water. Exposure to mold can cause health issues. You want to get rid of mold as soon as you notice it.

Mold can create a variety of health problems. According to the CDC these can include coughing, wheezing, asthma reactions and even pneumonia. To learn more about mold go here.


Mildew is another form of fungus. Mildew is usually black spots on the surface of your hot tub shell or cover. Mildew grows on the surface and is easily wiped off. Mildew grows in areas of high humidity and temperature. Mildew is common in showers and baths inside homes and anywhere else that is humid and warm.


Algae is a plant and not a bacteria. Algae grows in the water of your hot tub. Algae can grow in the water or on surfaces under the water. Algae can be different colors including green, brown, yellow, purple and black. Algae can show up as discolored water in your hot tub. Algae can make the sides of your hot tub feel slimy. Algae typically comes from unbalanced PH in your hot tub and dirty water. Algae grows faster in sunlight. If your hot tub is uncovered a lot it will grow algae quickly.

Step 2 – Shock your tub with sanitizer

Shocking your hot tub has nothing to do with electricity. Shocking your hot tub means using chemicals to kill off all bacteria that is growing in your hot tub water. This bacteria and organic material can feed mold and algae in your hot tub water. Use shock chemicals from a pool or hot tub supplier.

You should make sure your hot tub is at the correct Ph range before shocking. After adding shock to the hot tub water, let it circulate (no jets) for at least 20 minutes. Read the directions that came with your shock to learn how long to wait before it’s safe to touch the hot tub water.

Look here for a detailed look at how to shock your hot tub or watch the video below.

Step 3 – Empty your hot tub

The next step after shocking your hot tub is to drain it. You want to get rid of all the organic material and chemicals that were in your hot tub. The hot tub water is may be hazardous to plants and other vegetation. Use care in deciding where to let the hot tub water drain at. Don’t spill it over your prized flower bed or vegetable garden.

Most inflatable hot tubs have a drain valve to make emptying it easy. It may or may not have a hose fitting for directing the runoff.

Step 4 – Clean the filters

Take the filters off of your hot tub and clean them. If they are old replace them. Filters trap organic material and dirt that is floating around in your hot tub. Filters become great breeding grounds for bacteria. All the organic material is collected in one spot. That is why it’s really important to clean your filters on a regular basis.

Clean your filters with mild soap or detergent. Some hot tub filters can be put in your dishwasher for easy cleaning. Check the instructions that came with your filter to see if they are dishwasher safe. Be sure to clean them well and get rid of all the buildup in the filter. Wash it until it looks like a new filter. If you can’t then it’s time for a new filter.

Step 5 – Clean the surface of your hot tub

Next, we want to clean all the surfaces of your hot tub. A mixture of white vinegar and water makes a really good cleaner. White vinegar can kill 82% of mold species. To learn more about white vinegar and mold click here. Natural detergent or soaps are good choices also. Other good natural cleaners are water and baking soda. Natural detergent or soaps are good choices also.

You can also use a mixture of 50% water and 50% bleach. Bleach is not as mild as vinegar or soap so use caution.

You should never mix vinegar with bleach or baking soda. It will cause a chemical reaction that can release chlorine gas which is harmful to you.

If you like using chemical cleaners then be sure to use one that is safe for the PVC your inflatable hot tub is made from. Starbright Inflatable Boat cleaner is a good choice.

Use a sponge or cloth to clean your inflatable hot tub. Do not use a brush. Scrubbing with a brush can scratch and damage your inflatable hot tub materials.

You want to clean and wipe down every surface inside your hot tub. Make sure you get all the cracks and crevices. Bacteria and mold love to live in cracks. After cleaning rinse it off with clean water to remove the cleaners or chemicals. If your not going to refill your hot tub right away wipe everything completely dry.

The below video gives an in depth look at how to clean a hot tub. It is for a regular hot tub but almost everything applies to an inflatable hot tub.

Step 6 – Clean the cover of your hot tub

Clean the cover to your hot tub the same way you cleaned your hot tub. The cover can be a great breeding ground for mildew and mold. If your cover has an inflatable part and cover, make sure you take the inflatable part out and clean both sides of it. Clean the areas of the cover hidden by the inflatable part. Water from steam can collect above the inflatable part.

Step 7 – Refill your hot tub now that everything is clean

Now that everything has been thoroughly cleaned it’s time to fill the hot tub back up. Now that the hot tub is clean and free of mold, mildew and algae, follow good cleaning practices. This will keep it from returning.

How to prevent mold, mildew and algea from growing in your inflatable hot tub

Now that we’ve shown you how to clean mold from inflatable hot tubs, let’s take a look at a few things you can do to keep it from returning. The best way to clean mold, mildew, and algae from a hot tub is to prevent it in the first place.

Keep the PH at the correct level

You should maintain your hot tub PH level between 7.4 and 7.6. Bromine and Chlorine treatments are most effective in that range. Shock treatments only work while the water is in that range as well. Make sure you test your hot tub regularly to know for sure that the PH is in that range.

Use enough Bromine

Bromine kills the bacteria in your water. Now that your pH is in the correct range you need to use enough bromine to be effective. You want to maintain your bromine level at 1 to 3 ppm or parts per million. You should test your bromine levels when you test your pH until you figure out how many tablets you need to use.

Clean the filters regularly

Clean your filters regularly. At least once a week when you are using the hot tub often. Filters collect organic material that is floating in the water in your hot tub. It only does any good if you then clean the filter to remove the collected material from the hot tub. If you don’t clean the filters then they become a great breeding ground for bacteria, algae and mold. This defeats the purpose of filtering the water. Keep your filters clean and replace them when they can’t be cleaned anymore.

Shock your hot tub regularly

Adding bromine to your hot tub can only do so much for keeping your hot tub bacteria free. Shocking your hot tub mass kills the bacteria. If your hot tub has a strong chlorine/bromine smell that means that you have a lot of bacteria buildup. The smell comes from the byproduct of the bromine killing bacteria. A lot of smell means a lot of bacteria. Shocking your hot tub should allow you to get ahead of the bacteria and reduce the smell.

Drain and clean your hot tub at least every 6 weeks

Substances dissolving off people in the hot tub and falling into the water from outside build up. Over time it gets to be too much for the filter and chemicals to clean. This means it’s time to reset the system by draining the water and cleaning the hot tub. Every 6 weeks is a good drain and clean interval. You do not want to wait until mold and algae are growing in your hot tub to do a drain and clean. At that point you were already being exposed to the mold and all the health problems it can cause.

Have everyone shower and clean themselves before getting in the hot tub

The main cause of mold is soaps and lotions disolvoing off of people in the hot tub. Most of the organic material in the hot tub that bacteria feeds on comes off of our bodies. To keep your hot tub clean have everyone rinse off and cleanup before getting into the hot tub. This will slow down the buildup of organic materials, oils and dirt getting into your hot tub.

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About the author

My name is Doug Ryan. I am a homeowner and love having get togethers and finding the best things to make spending time at home easier and more fun. We spend a lot of time at home so why shouldn’t we have a great time there?  I decided to start Great Home Gear as a way to share my knowledge and enthusiasm for all things home living with everyone.