How to Get Rid of White Mold in a Hot Tub? (2 Methods)

You just came back from work and decided to get into the hot tub to relax. You went in and saw some white mold on the water. Now you can’t relax, you keep thinking about what these white flakes are and how to get rid of them.

If I just described you, then don’t worry. Taking care of white mold is easy and it shouldn’t take you a lot. Down below we have made a mini-guide on how to get rid of white mold in a hot tub, and how to prevent it. But, before we jump into the solution, let’s learn what white mold is so we can know what we are dealing with.

What is White Mold in a Hot Tub?

The white mold that you are seeing in your hot tub can look like white flakes or tissues (on the water). A lot of people confuse white mold with algae, even though they might cause the same problem, white mold isn’t algae.

If you just saw that you have white mold in your hot tub water then don't worry, there's an easy fix. We made a small guide where we explained how to get rid of white mold in a hot tub. We also have some great tips on how to prevent molding water from appearing in your hot tub.

The white mold grows into your plumbing, so if you are seeing white flakes on your water, then they have been inside the plumbing for a long time.

This problem usually happens if you have your hot tub filters outside. Except for the hot tub, the white mold can also appear on swimming pools, bathtubs. Taking care of white mold is easy, but it will take you some time.

Related Read >>> How to Get Rid of Foam in A Hot Tub?

Can You Use a Hot Tub With White Mold?

White mold is just a substance that looks like tissues in the water. White mold isn’t harmful to the people, only to the hot tub equipment because it can clog the equipment. While white mold isn’t harmful to people, it’s still not recommended to use the hot tub if you notice white flakes in your spa water.

How to Get Rid of White Mold in a Hot Tub?

While the chances of having calcium white flakes instead of white mold are very low, you still have to make a simple test to determine that. Usually, white molds are created because of a high level of biofilm and the calcium white flakes are a result of calcium scale deposits. So, how to know the difference? Make a simple test:

1. Test For White Mold or Calcium White Flakes?

To determine if you have white mold or calcium white flakes, you need to take 8 ounces of the water (with the flakes inside) and pour them somewhere. Then, add chlorine (bleach or liquid) into the collected water and wait at least 30 mins.

Once the 30 minutes have passed, check the water. If the flakes are still in the water then you are dealing with calcium white flakes. If the flakes have disappeared then you are dealing with white mold. If you are dealing with white mold then learn how to remove them down below:

2. Drain, Clean, Re-fill The Hot Tub

The white mold usually appears if the hot tub hasn’t been used for a long time, or if you didn’t clean the hot tub for a long time. So, it’s only logical to do a full clean of the hot tub. Plus, if you don’t clean your hot tub on a regular basis then you might have different problems that will appear very soon.

Drain the water, clean the hot tub, re-fill the hot tub. Add the needed chemicals, wait at least 1 day, and then do a test. If the pH levels are good and you see no white mold in your water then move to the next steps. When filling the hot tub, make sure to use a hose filter. This way you keep the unwanted chemicals outside of your hot tub.

3. Clean or Replace The Filters

As I said earlier, the white molds first start to appear in your plumbing, then in your filters, and then in your water. If you see white mold in your water, that means that they have been inside the filters for a long time.

To prevent the white molds to appear in your water after you have re-filled the water, it’s recommended to clean and rinse the hot tub filters. If you ask me, I would totally change the hot tub filters and get some new ones. But, cleaning the hot tub filters will do just as good.

4. Overdose Your Hot Tub With Chemicals

Once you cleaned the filters, it’s time to shock the hot tub. But, this time you have to “overdose” it. You have to add three or four times more chemicals than you usually do. Remember when I said that white molds are usually at the plumbing first?

We “overdose” the hot tub with chemicals so the chemicals can go through the plumbing and get rid of any white molds that are left. Leave the chemicals at least 1 hour before you drain the hot tub again.

Related Read >>> How Soon Can You Use Hot Tub After Adding Chemicals?

5. Drain The Hot Tub and Re-fill It Again

After you added 4 times more chemicals than you usually do and left them for at least 1 hour then it’s time to drain the hot tub. Drain the hot tub, and fill it again with normal and clean water (using a hose filter).

Shock the hot tub again, but this time use a normal amount of chemicals. Leave the chemicals for a while and then do a water test to balance things out. The normal pH should be 7.0- 7.5. Once you balance things you then you can use the hot tub.

Related Read >>> How to Get Rid of Cloudy Spa Water?

Method 2: Decontaminate The Hot Tub

If the first method doesn’t work then you can use this method. You need to have chlorine and know how many liters of water your hot tub has.

1. Add Chlorine To The Spa

Calculate how much water your hot tub has, and add 3 ounces of chlorine per 400 liters of water. A 4 person hot tub approximately holds 1,250 liters of water, and a large hot tub (7 persons) approximately holds 3,000 liters.

So, if you have a large hot tub (3000 liters of water) you need to add 22.5 ounces of chlorine to the hot tub.

2. Distribute the Chlorine Water Through the Plumbing

The chlorinated water has to go through the plumbing too. So, you need to make sure that the jets, waterfalls, and all other valves are open.  You also have to attach a hose to the drain valve because if you don’t, the chlorine won’t go through the plumbing system.

3. Wait 72 Hours

Once 24 hours have passed check the chlorine levels using a test strip. If the chlorine levels are lower than the maximum then add more chlorine. Check again after 48 & 72 hours and test the chlorine levels. If you notice that the chlorine levels have dropped then add more chlorine.

This process will help you get rid of water mold in your plumbing system and in your hot tub water. But, you will still have white flakes in your hot tub. So, after 72-hours have passed your need to drain the hot tub water, clean the hot tub water, clean/replace the filters, fill and shock the hot tub. Don’t use the hot tub while doing this method.

Will Algaecide Kill White Water Mold?

Algaecide is used in pools and hot tubs to kill algae. We explained earlier that while most people think white mold is algae, it isn’t. But, white mold and algae are both a type of fungus that do the same harm in your hot tub.

So, yes you can use algaecide to kill white mold in your spa water. You need to add 1 ounce of Algaecide per 400 liters of spa water.

How to Prevent White Mold in a Hot Tub?

Getting rid of white mold in a hot tub is one thing, but preventing it from happening again is another thing. You don’t want to drain and refill (2 times) the hot tub every day. There are a few things that you can do to prevent that from happening:

1. Clean The Hot Tub Once a Week

If you clean your hot tub regularly then you don’t need to worry about white water. Clean the surfaces of your hot tub, especially the ones you use more, with a scrub brush. Make sure to test your water regularly, and if you see that your water levels aren’t what they are supposed to be then add the needed chemicals.

Except for the hot tub surfaces, you should also clean the filters at least once a month. When cleaning filters, don’t just use water, make sure to use chemicals to fully clean it. If your filters are old (1 year or more) then it’s recommended to replace them with a new one.

2. Clean Things You Use in the Hot Tub

Except with our body, the hot tub water also gets in contact with a lot of other stuff we bring with us. Usually, hot tub toys or any other floating should be cleaned before you put them into the water. Just rinse them.

Also, make sure to clean other hot tub parts as well. Especially, the ones you use the most, this will help you get rid of other bacterias the hot tub might have. Take a wet cloth, mix it with a little soap, and start rubbing the parts you usually touch/sit. Make sure to clean it with water after you use soap.

3. Shock Your Hot Tub Regularly

Even if you don’t have white water molds you should shock your hot tub regularly. I recommend shocking the hot tub especially after heavy use, that’s usually the time when white water molds and other bacterias are created

Related Read >>> Can You Use Liquid Bleach in a Hot Tub?

No More Mold

And that’s all you need to know about how to get rid of white mold in a hot tub. As we mentioned a lot in this article, the main reason why you get white water into your hot tub depends a lot on your tub maintenance.

You should clean your hot tub weekly. You should shock your hot tub on a regular basis, and you should check your water levels on a regular basis. If you do these three things, then you won’t have any problems with white mold.

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