How Do I Remove Calcium Buildup In A Hot Tub? 3 Easy Methods!

Calcium buildup is one of the challenges hot tub owners face. Knowing the best way to remove or prevent these scaly buildups is crucial to spa maintenance.

Calcium deposit or buildup can be removed by vinegar scrub, bleach and dishwasher detergent rinse, or whirlpool rinse. You may want to scroll down to learn how each of these methods works.

I could remember taking a long vacation in the Bahamas in 2009. By the time I came back home, I noticed white flakes all over my hot tubs. I did not know what it was until I called my spa dealer to complain.

He told me that it’s a calcium buildup. And he directed me on what to do to get rid of it.

What is calcium buildup in a hot tub?

Calcium buildups are the white flakes or moles that float in the hot tub. They also gather by the sides of a hot tub. When once there is excess calcium in your hot tub, there will be a buildup since the filtration system seems not to be able to handle it. This mostly occurs in a hot tub that Epsom salt and other salts are added to the hot tub for whatever reasons.

What are the causes of calcium buildup?

Calcium buildups in a hot tub can be caused by calcium scale deposits and biofilm

Calcium scale deposits

This kind of calcium buildup happens when there’s an excess of calcium in the water. As more and more salt is added to the hot tub, calcium will accumulate resulting in white flakes forming on top of the water.

The biofilm

This is made up of natural materials that are shed by users of hot tubs, which appear like an overgrowth of white water mold. Biofilm happens mainly when you do use your hot tub for a while and for this period it has not been thoroughly cleaned. The moist and warm nature of the hot tub will be a good place for mold to grow and it will bring the white flasks.

How to know the type of calcium buildup

As stated above, there are two causes of calcium buildups. You need to know what is truly causing the white flakes you are seeing in your hot tub. Knowing the root cause of the calcium buildup will help you to know the best way to get rid of them and as well prevent their occurrence.

The following steps will help you to know the actual cause of the buildups:

  • Use a bowl or cup to scoop a 4-5 ounce water from your hot tub (make sure the flakes are floating in there)
  • Now, add about 15-20 drops of liquid chlorine or bleach
  • Let the water sit for about 30 minutes

Now take a look at it, if you notice the white flakes have disappeared, know that it is caused by mold which is biofilm buildup. But if the white flakes are still floating, it simply means that the buildup is caused by calcium scale deposits.

How do I remove calcium buildup in a hot tub?

There are several ways you can use to get rid of calcium buildup in your hot tub. We will be discussing each of the causes. However, there are still general methods you can use to clear the buildups effective irrespective of the cause.

Starting with the biofilm, if you test and find out that the calcium buildups are caused by biofilm, you can specifically get rid of the calcium buildup by doing the following:

  • Clean the hot tub thoroughly especially the filters, hot tub cover, and skimmer. Clean all parts of the hot tub.
  • Shock the water in the hot tub to kill all the bacteria in it.
  • When done with the shocking, drain your hot tub completely. Wipe all things thoroughly and clean it again.
  • After you successfully do this, fill your hot tub back with water.

For calcium scale deposits

You would have to bring down both the pH and alkalinity levels of your hot tub. These levels need to be balanced. The truth is that when once the pH levels in the hot tub are high, these white flakes must surely appear.

So you need to bring the level between 80-130ppm to keep it low. There are products you can apply to bring down these levels.

Now, if you are not interested in knowing the cause, you can easily use the general methods of removing calcium buildups.

Note: you should always be careful with the chemicals you will use to scrub your hot tub. You need to be sure they are not abrasive. This will help you not to mess up the pH balance of water in your hot tub

Method 1: vinegar scrub


  • Drain the hot tub
  • With a towel, remove the loose residue or moisture
  • Let the hot tub dry
  • Get both distilled water and vinegar in the ratio of 1:1, and then pour the mixture into your spray bottle
  • Now, spray the mixture on the hot tub shell. Allow it there for about 5 minutes
  • With a nylon brush, scrub around the jets and surfaces. Scrub tough spots as required
  • If the buildups haven’t all been removed, you can make a paste of distilled water and baking soda. Scrub with the paste still using the nylon brush. You can now wipe out the remaining baking soda with a wet cloth.

Method 2: the bleach and dishwasher detergent rinse

You would not need to scrub with this method unlike the method above. With this method, you would need to drain and refill the hot tub twice. This rinse is to aid in breaking up the deposits that are on the shell and in the jet lines.


  • First, check the waterline. Make sure the water in your hot tub is above the jet line openings.
  • Put in your hot tub ½ cup of dishwasher detergent and 1 cup of bleach. But be sure that your dishwasher detergent used is compatible with bleach. So check the manufacturer guide on your dishwasher detergent before mixing the two.
  • Then put the jets on high, leave it that way for about 15 minutes.
  • Now, drain the water in your hot tub.
  • Let your hot tub be refilled with hot water.
  • Put back the jets on again for another 15 minutes.
  • Drain it again and you are done.

Method 3: whirlpool rinse

This method will first need one removing the white flakes from the water by using a net to remove the debris in the hot tub. After removing the white flakes, as many as possible, a product called Whirlpool Rinse will be used before draining the hot tub.

The whirlpool rinse can be bought in the usual spa store. This product is a deep cleaner for hot tub interior plumbing. It removes grease, cleans, and breaks down calcium buildups in the hot tub.


  • Let the water in your hot tub be hot. Whirlpool rinse is almost ineffective in cold water.
  • Next, remove the tub filters to avoid clogging before adding the whirlpool.
  • Now remove your hot tub’s headrests and pillows.
  • Turn off the air control dials i.e. move them counterclockwise. Then turn to the middle your diverter values. This will enable that all the plumbing is cleaned.
  • You can now add ½ bottle about 250ml of whirlpool rinse straight into your hot tub’s water.
  • You can start running your jet pumps; it will be for 2 hours. There will be intermittent turning on though for about 20 minutes per time. Do not allow the time to exceed 2 hours
  • Then drain your hot tub.
  • Wipe down the shell, and then refill it back.

Note: if your calcium build-up after cleaning is still isn’t completely removed, i.e. you can still notice some white flasks in your hot tub, you will need to repeat this whole process until you completely get rid of the calcium buildup.

How to prevent calcium build up in your hot tub

The good news is that calcium buildup isn’t only removable, it is also preventable. The best thing you can do for your hot tub is to prevent anything that will ruin it.

Some damages can’t be undone or put back to their original state. So it is better to always take preventable measures seriously. The following can always be done to get your hot tub from having calcium buildups.

  • You need to use a test strip at least once weekly to ensure that the water chemistry of your hot tub is properly balanced. The earlier you make an adjustment to help stop any calcium buildup, the better for you. You should start with some adjustments to the alkalinity level first. Then re-test later in the day to be sure, before adjusting the pH level if needed. The few minutes you would spend balancing your water will be a lot helpful for you in the long run.
  • Don’t leave your hot tub for too long without cleaning it. If you do, you would end up having calcium buildups which might become very stubborn. So, regularly clean your entire hot tub especially the jets, sides, and other features.
  • Replace your filter immediately when needed.
  • Mostly use only quality water and invest in a water softener. Avoid the use of hard water as it easily enables calcium deposits to build-up.
  • Go for only high-standard spa chemicals for your hot tub, especially when you want to restore your hot tub’s alkalinity level or the pH balance.
  • Have handy a scale preventer and use it regularly. This will help to break down existing particles. It will help to prevent the problem from happening again.

Reasons you should remove calcium buildups from your hot tub

  • To prevent damages to your hot tub features: The calcium buildups left behind by whatever causes will affect the walls and features of the hot tub. And when once these are damaged, you need to replace them or their functionality reduces. So, checking to do away with calcium buildups in your hot tub is necessary, to avoid it damaging other things in the hot tub.
  • It helps keeps the filtration system from clogging: The main essence of the filtration system is to filter out contaminants in the water. But when once there is a buildup like the calcium deposits, this system becomes clogged. Of course, as time goes on, it will become less effective and filters less dirt and debris in the hot tub. So, remove any calcium buildup in your hot tub as soon as you notice it to save your filter.
  • It enables a safe hot tub for use: There’s no way you will have external bodies in your hot tub and it will safe for use. When your filter is clogged and cannot filter out effectively the dirt in your hot tub, the hot tub wouldn’t be safe for a soak. So, remove all calcium deposits from your hot tub to enable you to have a safe hot tub.
  • You would avoid unnecessary spending: Once you get rid of calcium buildup in your hot tub, you would be preventing it from damaging the components of your hot tub as fast as possible. If your hot tub components get damaged in the process, you might need to repair or replace them. To avoid spending unnecessarily, you need to get rid of calcium buildups as soon as you notice them.


Getting rid of calcium buildups in your hot tub is very necessary. You need to know the different ways by which you can achieve this – we discussed some of them in this piece. You just need to check them out and go for the one you deem fit for you. Happy soaking.

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