Calcium Build Up in Hot Tub Water

The flakey substance you see is a calcium scale, similar to what you might find built up on the inside of your kettle.

Calcium build up is usually caused by high pH levels in the hot tub’s water, which is why testing and balancing the water regularly is important. 

Flakes of calcium are often most noticeable in the water after you drain & re-fill your spa, as the calcium built up in the plumbing reacts to cold water being added and falls off the pipes and makes it’s way into the main body of water.

The good news is that Calcium build up is both removable and preventable!

Removing Flakes & Scale From Your Hot Tub

If you open your hot tub cover and it looks like it has snowed in your spa, here is how to get everything nice and clean again!

To remove the deposit of calcium flakes from you water, use a net similar to a pool skimmer to remove as much debris as you can.

Once you have removed as many of the flakes as possible, you are going to have to use a product called “Whirlpool Rinse” before draining your hot tub.

Whirlpool Rinse is available at all of our stores, and is a deep cleanser for your hot tub’s interior plumbing that cleans, de-greases and breaks down calcium build up in the plumbing. Here is a step-by-step guide to using Whirlpool Rinse in your hot tub:

* Make sure the water is hot, Whirlpool Rinse is not effective in cold water.

* Remove your hot tub filters before adding Whirlpool Rinse, so they do not get clogged.

* Remove your hot tub’s pillows/headrests (You can give the pillows a clean while your tub is draining).

* Turn your air control dials off (move them counterclockwise) and turn Diverter Valves to the middle to ensure that all of the plumbing is cleaned.

* Add 1/2 bottle (250ML) of Whirlpool Rinse directly to your hot tub’s water.

* Run all Jet Pumps for 2 hours (You will have to turn them on every 20 minutes). Do not leave Whirlpool Rinse in the hot tub water for more than 2 hours.

* Drain your hot tub as usual.

While the filters are out of the hot tub, you should clean the pleated filter with a product such as Cartridge Cleaner or AquaMagic to remove calcium flakes and other debris. Do not clean your disposable Sundance Micro Filters – They should be replaced if they are dirty/slimy/coated in Calcium flakes.

Once your hot tub is drained, wipe down the shell and re-fill as usual.

If you notice the surface feels “gritty” from calcium build up, use a warm water / vinegar mix to break it down and leave the shell nice and clean. Avoid using household cleaning products on your hot tub interior as they will have a negative impact on your new water and your acrylic shell.

If the calcium build up in the plumbing is really bad, and you see more flakes when you re-fill the spa, you may need to repeat this process a second time to deal with the issue completely.

We recommend the use of Whirlpool Rinse once a year to keep the plumbing in great condition.

Preventing the Build up of Flakes & Scale

Calcium hardness levels in tap water vary from City to City and will effect how you have to treat your hot tub water once it is filled.

In some locations (such as Carlisle, Georgetown & Milton) the water is very hard, and the need to reduce the pH level straight away is vitally important. The longer the water is unbalanced, the faster the build up of residual calcium.

If you have hard water, you should add Prevent II to your water on a weekly basis in addition to the Spa Marvel Conditioner. Prevent II is a product designed to prevent staining and reduce the build up of scale.

After adding the Prevent II to your hot tub water, wait at least 5 hours and then use an AquaChek 6-in-1 test strip to test the balance of the water.

Make adjustments to the Alkalinity level first if required, then re-test later in the day and adjust the pH if needed. Starting with well balanced water will make the hot tub easier to maintain for the long term. Once your water is balanced, add the appropriate level of sanitizer to the water and your spa will be ready to use.

For hard water, Prevent II should be added on a weekly basis, at least 5 hours apart from the addition of any other chemical being added to the water, this will prevent scale formation and will help clarify cloudy water.

Use a test strip at least once a week to ensure your water is correctly balanced and make adjustments if necessary. A few minutes spent balancing your water will save you a lot of hassle down the road!

If you are unsure on the balance of your water, feel free to bring a sample in to any of our 6 locations (Burlington, Hamilton, Mississauga, Oakville, St. Catharines & Vaughan). We will gladly test it for you and advise you on how best to treat the water to keep it safe, balanced, clean and clear so you can use your Sundance Spa on a regular basis.