How to Get Rid of Algae, Mold and Mildew in Your Hot tub

hot to get rid of algae and mold

Regular maintenance of your hot tub can guarantee you trouble free performance for a long period. This maintenance doesn’t require much effort and time since it involves simple activities like testing and adjusting the hot tub water weekly, monthly cleaning of filters and draining the old water and refilling the hot tub at least twice a year or as recommended by your water care system.

Keeping your hot tub clean and well maintained always will prevent the growth of algae, mold, and mildew. However, if you see some traces of growing algae, mold and mildew in your hot tub, it’s essential to determine the cause, how to eliminate them and prevent them from growing back in the future.

How to Remove Mold from a Hot Tub

A clean and well sanitized hot tub won’t allow the growth of algae, mold, and mildew. However, if minor problems occur, you can simply adjust the pH levels to enhance a proper balance.

Steps to get rid of algae and mold

Below is a step by step guide on how to get rid of algae, mold, and mildew:

1. Make up a solution

The process of making a cleaning solution is very easy since you can use ingredients around your house. It’s a straightforward process that can help you save a lot. Take a little detergent and mix some amount of bleach and then add one gallon of water. This can effectively be used in eliminating the problem of algae, mold and mildew growth.

2. Prepare for the cleaning

Make sure you remove all hot tub covers before you start scrubbing all parts of the hot tub using the solution you made. During the cleanup, ensure your hands and eyes are well protected because you’re using a bleaching agent that can cause stinging and burning. You can also use a ventilation mask to protect your whole face. Properly scrub all parts of the hot tub because it will help in later steps.

3. Brushing

Use a soft brush or sponge to clean all parts of the hot tub where covers rest. Also, ensure you clean the covers to prevent the problem from coming back after the cleanup. In parts where a huge brush can’t effectively remove all these substances, you can use an old toothbrush.

4. Foam encasements

Make sure you thoroughly clean all covers and foam core encasement. Use the solution you made or a cleaning agent. Cleaning these parts is essential because they seal off and protect the hot tub. Failure to clean them properly can make the bacteria to easily enter your hot tub in the future.

5. Drying

Place the foam cores and covers in a dry area. Placing them out in the sun is the best option since they’ll dry quickly. The heat from the sun can also kill off the bacteria and mold you may have missed during the cleanup process.

6. Spray an anti-bacterial agent

After drying out all covers and the hot tub, spray an anti-bacterial agent to ensure the hot tub is free from bacteria and make it ready to use.

If there is extreme contamination, sanitize the water after you refill the hot tub, drain it and refill again. Although it may seem to be a time-consuming process, it’s worth the effort to completely eliminate all the contaminants and restore your hot tub’s normal condition.

Other products that can be used include white vinegar with an acidity pH level of 2.5 or high as 4, olive oil, baking soda, rubbing alcohol, and major eraser. It’s essential to carefully read the instructions provided by the manufacturer.

Causes of algae, mold, and mildew in hot tubs

All the three are different organic substances where algae come as plants, whereas the others are fungi. All these present almost similar challenges to the owners of hot tubs. In most cases, algae can appear in many forms and colors ranging from white to black to green to yellow. Depending on the color, the water in the hot tub will change accordingly. Also, you can notice their presence due to the slippery and slimy feel on the sides of the hot tub.

Algae generally form as a result of imbalanced pH levels in water or if there are small quantities of chlorine and bromine than the required. You should also remember that sunlight favors algae growth, which is the reason why you shouldn’t leave the hot tub uncovered for a long period of time.

On the other hand, if you notice the presence of floating white slime or discolored black or white patches in your hot tub, it’s because of mold and mildew. You can easily wipe mildew unlike mold which shows that there’s a more intensive infestation. Mostly, mold tends to form in neglected spas. They normally form as a result of lotions, soaps among other substances transferred from the skin of the user to the hot tub. Mold and mildew will generally appear on the cover of the hot tub before spreading to the water.

How to prevent algae, mold, and mildew from returning

If you leave your hot tub covered when not in use, ensure all filters get cleaned and even replaced more regularly. Also, you must test and maintain your hot tub water so that you don’t experience challenges with water contaminants which can have a negative effect on your health.

Most problems associated with your hot tub largely depend on the level of sanitation. For instance, if you bring a used hot tub to your home, it’s essential to check if there’s mold infestation simply because the previous owners may have had insufficient care. If you buy a used tub, ensure you shock the water, drain it and later clean it before refilling so that you can be sure you have a clean and sanitary hot tub.

In conclusion, ensure you have a routine maintenance schedule to make it easier to prevent the growth of algae, mold, and mildew. Remember that all these contaminants can affect have negative health effects such as allergic reactions, asthma, poisoning among other issues.

Last update on 2024-04-13 / Affiliate links / Images from Amazon Product Advertising API


  1. Laura

    I have a hot tub inside the house. It is a new one, used only for six months last year (I had another one before for several years). Last Fall as usual I emptied it, cleaned it and thoroughly cleaned the filters to leave it dormant for the winter and Spring. I had a lot of things in my mind and did not proceed the way I used to. I re-installed the filters and put the cover on the spa; normally I don’t put the filters nor the cover so if there is some remaining humidity, it will go. Result: when I removed the cover in order to start it for a new season, there was a terrible odor, there was mildew inside the cover, on the rubber pillows, the filters and in the pipes where the filters are anchored.

    I washed the cover outdoors and the rubber pillows and they look OK. The filters are presently in buckets with a filter cleaning solution until tomorrow: will that be enough or do I need to replace the filters- expensive? But what can I do for the pipes? Is there a product or cleaning solution that is safe for the spa parts and will remove all mildiew (mold?) if I fill the tub, run it and empty it? I am scared because I have a lung problem. thank you.

    • Preston Allen

      If you fill the tub, add in a gallon (or more, it won’t hurt anything) of white vinegar. Turn the jets on and let them run for 20-30 minutes. Drain, rinse thoroughly. And let it dry to eliminate the vinegar smell. Then refill, properly add your chemical balance, and let the filters work for a day or so and you should be right as rain!

      White vinegar is a wonderful cleaner for inside the pipes and jets where you cannot reach to clean. As it will kill algae, mold, and germs without damaging any materials. Just don’t pour it straight in without water. It must be diluted and not allowed to sit on a location (for soft vinyl tubs). Hard tubs are quite durable.

  2. Kerris

    I have emptied and cleaned our hot tub today (the wiring tripped and it had been left turned off for a while) whilst it’s all clean there are some pink stains on it now – how would I go about getting these off please?


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