How to Fix Cloudy Hot Tub Water: 7 Step Guide [Best Results]

By James Brockbank •  Updated: 02/12/21 •  15 min read

How to fix cloudy hot tub water?

Cloudy water is often a result of chemical imbalance within your hot tub. This imbalance leads to insufficient sanitizer levels causing bacteria and other organic material to spawn in the water making it cloudy. To prevent this, add 30g (1 capful) of oxidizer to the spa. Next, add another 30g of sanitizer (either chlorine or bromine) to clear the water. Sanitizer levels should be between 1-3 PPM for chlorine or 2-6 PPM for bromine.

Stop wasting time and money with hot tub maintenance and confusing water chemistry! The Hot Tub Handbook and Video Course will help keep your hot tub balanced, sanitized, and crystal clear all the time.

Check out my list of high-quality hot tub products to help keep your hot tub clean and running great all year long!

My recommended product to help you test your hot tub or pool water for accurate pH, alkalinity, bromine, and chlorine readings is the AquaCheck Trutest Digital Reader.

Usually, a cloudy hot tub water problem requires a little bit of troubleshooting before finally going for a solution.

It is most likely that your problem is one of the below situations. If you have heard that “Bromine makes your spa cloudy” or something like that, do not act on it without proper knowledge. Always read in detail about it and try to understand why it happens.

Tips for maintaining clear water are discussed at the end.

Check out our full article on how do hot tubs work for beginners to understand the different components and what hot tubs are made out of.

Let’s get started!

What Causes Cloudy Hot Tub Water?

Cloudy water in the hot tub can be caused by various reasons. Sometimes there could be two reasons causing the same problem. We’ll discuss each reason in detail below.

Low Water Sanitizer Levels

Did you notice the cloudiness of water after heavy use? Then low water sanitizer levels could be what’s causing the hot tub water to be cloudy. That’s why I use hot tub sanitizers; to remove bacteria and other organic contaminants. If the rate of things being added to the water is greater than the speed of the contaminant being removed, cloudiness can appear.

The sanitizer levels actually disturb the hot tub pH, and high pH makes the water cloudy. High pH levels cause different chemical substances in the water to react with each other when the conditions are right. Insoluble solid substances are produced, and a suspension develops.

Check out our full article on how to raise pH and what I recommend.

When sanitizer levels fall below 1.0ppm, the foreign particles take over and make the water cloudy. There is no chemical reaction but the dead skin, body oils, and other matter causing the cloudy water.

Our recommended product to raise pH in hot tubs is Spa Essentials pH increaser Granules.

Our recommended product to decrease pH in hot tubs is SpaGuard pH Decreaser.

High Calcium Hardness and pH Imbalance

If you are from an area where there is hard water, high calcium amounts can make your hot tub water cloudy. Check the total alkalinity level (TA), pH, and calcium hardness and put them under recommended ranges.

Calcium makes the water more alkaline, and that causes cloudiness. So, make sure the calcium hardness levels are not greater than 300ppm. A chemical balancer is an effective method of adjusting the calcium hardness, pH, and alkalinity of water.

Similarly, if the total alkalinity levels are more than 150ppm, metal carbonates can build up, making the water cloudy. Even if the cloudiness is not a problem, you should keep the total alkalinity under the limit. If they rise too much, it can become difficult to control them. You can use a pH reducer to keep the levels under 100ppm.

To raise total alkalinity I recommend Spa Essentials Total Alkalinity Increaser.

Total Dissolved Particles

A hot tub that has held water for more than four months develops high TDS levels (total dissolved particles). Water only absorbs chemicals to a certain amount, and after that, the particles just move around in the water as solids. These undissolved particles can cause the cloudiness of water. Now is the time to drain and refill the hot tub. You don’t have to wait for the water to become cloudy, as you can check the TDS levels. If the TDS level is above 1500ppm, then replace the water.

Dirty Hot Tub Filters

The most common reason why spa owners face cloudy hot water is dirty hot tub filters. If you forgot to clean the filters, now is the time.

The job a hot tub filter does is catch the “gunky stuff” floating in the water. Over time, various types of small matter can get stuck in the filter and reduce the filter’s efficiency to do its work. The filter becomes overloaded with grease and other contaminants, and its effectiveness decrease over time.

Another possibility could be a bad quality filter. Dirty water might be escaping the filter and causing cloudiness. Make sure that you have positioned the filter correctly. If the problem still remains, try replacing the filter.

Hot Tub Pump Problems

There are plenty of pump problems that can cause cloudy hot tub water. The amount of water filtered is totally dependent on the water pump. It is possible that the amount of time the spa pump is running is not sufficient. So, to increase the amount of filtering, run the pump at high speed for two hours daily.

Another pump problem could be low or no water flow from the pump. The reason for this could be either an airlock or spa pump failure. For the airlock, loosen the union on the pump to allow the trapped air to escape. Run the pump with the union loosened and tighten it when the water starts to leak out. This ensures that no air is trapped inside. On the other hand, if the pump doesn’t turn on, check the GFCI button. Check for bad wires or another electrical supply problem.

If the pump runs and the water flow is low even after releasing the airlock, check for a clogged spa impeller. Due to the small size vanes on the impeller, leaves and stones block it easily. This reduces water flow and decreased filtration. Another possibility could also be a broken impeller, thus giving zero water flow.

If you’re having hot tub pump problems check out our full article on the subject for more information.

Biofilm Problems

Biofilms quickly build up in spas that have been left open for some time. It is a multicolored slimy bacterial film that coats the surface of the hot tub water and your pipings’ inner side. If you have ever touched your hot tub pipings’ inner side when cleaning, you know what it is.

Water becomes cloudy when excessive biofilm builds up. You can even see slimy materials floating on the surface of the water. Stagnant water is probably the main reason why biofilm grows. But if the climate is humid, biofilm can grow in the pipings even if the hot tub is empty.

Cosmetics, Soap, and Lotions in the Spa Water

Who doesn’t use cosmetics these days? When you soak in a hot tub, these cosmetics get dissolved in the water. This includes hair oils, sunscreen creams, detergents, and various other things.

Sanitizers don’t analyze the chemical before breaking it down and sending it onto the filter. Thus, the sanitizer is used up more quickly, and the filters get dirty, causing the water to become cloudy. Spa enzymes have proved to be an effective way of removing this greasy gunk and reducing sanitizer demand.


How to Fix Cloudy Hot Tub Water: 7 Steps

We’ll go through the 7 steps to fix cloudy hot tub water below.

1. Test the Water

Check the sanitizer levels and pH of the water and adjust them to the recommended levels. There are test strips available that are cheap to buy. If you own a spa and have to check more often, then buy an electronic checker.

Bromine and chlorine levels should be 2-3 ppm and 3-5 ppm, respectively. Check if it has solved the problem.

Keep the pH between 7 and 7.2 as high pH can make the water cloudy. Make sure to shock the water after the hot tub has been heavily used. If the chlorine shock is still causing cloudiness, then use a non-chlorine one.

I recommend these water test strips from JNW Direct Pool and Spa to test your water.

2. Clean the Hot Tub Filters

If you haven’t cleaned your filter in a long time, then use a filter cleaner. As it might have become filthy and stuffed with oils and biofilm. As the oils won’t come off just by rinsing with a garden hose, a chemical compound must be used, such as a filter cleaner. The filter cleaner breaks the greasy stuff down and restores the full water flow. The filter should be replaced after one year or 10 cleanings.

If you use a DE filter, then check if it is ripped. DE filters are becoming more common, and there is a good chance that you use one too. They contain rocks finely powdered and are sealed in a bag that allows the water to go through. If the bag gets ripped by something sharp, the powder enters the water and the spa water becomes cloudy.

Check out our full article on how to clean hot tub filters step by step!

Hot tub filters come in all shapes and sizes.

Our recommendation for larger filters is Guardian Pool/Spa filters.

Our recommendation for the smaller filters is Intex filters for inflatable hot tubs.

3. Shock the Spa

Cloudiness is mostly due to the increased proportion of greasy and dirty materials in the water. So, the best way to remove this stuff is to shock the water. In fact, shocking is done only to flush all the yucky stuff out of the hot tub. Use chlorine or bromine shocks as per manufacturers’ recommendations.

Don’t forget to clean the filters afterward as they get filthy after shocking.

Check out our full article on shocking your hot tub and the steps to do it properly.

Below is our recommendation for non-chlorine.

Our recommendation for chlorine shock.

4. Add Chlorine

Adding chlorine to water is equivalent to shocking.

Keep the sanitizer levels under control by checking with check strips. Add chlorine accordingly.

Add small amounts of chlorine until the water becomes clear again.

Check out our full article on chlorine tablets and how to administer them.

Below is our recommendation for chlorine tablets.

Our recommendation for a chlorine dispenser.

5. Remove and Add Fresh Water

Another effective method for cloudy water is to add fresh water to the hot tub. It is possible that the water is too contaminated, and the use of sanitizers and shockers is just useless. These things are expensive, and their use also decreases the filter’s lifespan. So, it is better to just replace the water than to spend time removing impurities.

If your hot tub water hasn’t been replaced in four months, then do not waste your money on sanitizers or oxidizers. Just drain the water and refill it with fresh water.

Cloudy water should be gone after you do this if there is no pipe clogging and excess biofilm.

6. Flush the Circulation System (Solve the Biofilm Problem)

Do not keep the hot tub empty nor leave the hot tub open for too long. Run the pumps on low for two hours daily. Always change your filter after 6-12 months, depending on the use of the hot tub. It helps to trap as much biofilm as possible.

Reducing the pH of water makes it difficult for the biofilm to grow in colonies. Keep the pH to 7.2 or shock the water to increase chlorine levels significantly after shocking, clean the filters. The filters can become really dirty, and the reason for cloudy water.

Clean the pipings with jets of water to remove biofilm. Do it every four months when you refill the hot tub with fresh water.

7. Drain, Clean, and Fill the Hot Tub (Last Resort)

If nothing has worked, then give the hot tub a bath. Empty it and thoroughly wash it and unclog the pipings while removing any possible biofilm. Add line flush product to the water before draining. This would dissolve all the biofilm accumulated in the pipes. Allow the water to circulate for 30 minutes after adding line flush product. You will see foaming on the surface of the water, but this is normal.

When filling it up again, check for airlocks and pump malfunction, and low water flow. If you have diagnosed the pump failure, check out this article to analyze the pump failure problems.

How to Prevent Cloudy Hot Tub Water: 6 Steps

Prevention is better than the cure. You should always be taking care of your hot tub so that you don’t have to worry about cloudy water. Here are some quick things to think about to prevent cloudy water.

1. Always Monitor Your Spa

Check the pH, sanitizer levels, and calcium hardness daily. These variables change significantly after heavy use of the spa. Even if you are not using the hot tub, keep the sanitizer levels sufficient in the water.

2. Keep Your Hot Tub Filters Clean

Always keep the filters clean and replace them after 6-12 months.

3. Refill Your Hot Tub on a Regular Basis

Refill your hot tub with fresh water after four months to remove any impurities. Never refill your hot tub without proper cleaning.

4. Shock your Hot Tub

Shock your hot tub after a week or two, depending on the use. Do not enter the water immediately after shocking. High levels of chlorine can irritate your skin.

5. Keep Your Spa Cover On

Always keep a cover on the hot tub to prevent debris from falling in the tub. Never leave the spa open. Check for possible holes or damage to the spa cover.

6. Make Sure the Pumps are Working

Check if the pumps are working correctly and the water flow is sufficient. This is a very unusual case, but you should consider everything before finally calling a professional.

Make Sure the Chemical Balance is Correct

Chemical balance is probably the most crucial factor here. If pH is high, or calcium hardness is high, or alkalinity is not under control, water cloudiness can worsen. Sanitizers must be used according to the specified ranges provided by the manufacturer.

Chemical balance disrupts greatly when the spa is heavily used as cosmetics, and dead skin gets dissolved in the water using up the sanitizer.


Consider Using a Water Care Monitor

Monitoring the health of your hot tub can often be challenging if you are not testing the water on a regular basis. This can also be a problem if you go on holiday or you are unable to take care of your hot tub due to mobility issues.

The pHin Smart Water Care Monitor for pools, hot tubs, and inflatable spas continuously tests the water and alerts you when to add chemicals with the integrated mobile app.

The mobile app will inform you when to add chemicals such as chlorine, and how much chemical is recommended. This is done by entering your hot tub or pool’s unique dimensions.

Simply scan the bar code of any chemical brand and the pHin app will calculate how much chemical is to be added to the water. Most products and brands are recognized by the application.

The pHin device will sample water more than 1000 times per week to give you an accurate reading compared to using test strips.

The pHin device works with different water types including chlorine, bromine, and saltwater hot tubs, swim spas, inflatable hot tubs, and pools.

This unique device comes with a lifetime warranty to ensure your water remains clear and ready for you to use at all times.

Have People Rinse-Off Before They Use the Spa

Having people rinse off before they use the spa can save you some sanitizer cost. Thus, you won’t see cloudy water as often. Rinsing before spa use removes any possible lotions, oils, cosmetics, and other contaminants people might be carrying. Don’t use any soap when rinsing off. It can be very beneficial for someone who owns a spa. Make it your spa policy.

Never wash your swimming suits with detergents as some detergent remains. Just rinse it off with hot water after a soak. Do not allow any use of sunscreen while using the hot tub.

How to Fix Cloudy Hot Tub Water: Conclusion

how to fix cloudy hot tub water

Hot tub problems arent very complicated and require just a bit of troubleshooting.

Whenever checking the chemical levels, always be accurate. Do not use substandard equipment as that could also be the problem of cloudy water. Keep your hot tub clean so you don’t have to use shocks or high chemical usage. These chemicals increase the pH significantly for a short time and damage the hot tub parts. This increases the scaling and blockage of the pipes.

Testing the water is crucial. Check the chemical levels after heavy use of the hot tub and then adjust the levels accordingly.

I hope you found this article about cloudy hot tub water helpful.

Thanks for visiting

James Brockbank