How to Prevent and Remove White Flakes in a Hot Tub

Have you ever noticed white flakes floating in the water or gathering by the drain of your hot tub? You’re not alone! The good news is that this isn’t uncommon and there are ways to remove it and prevent it from happening in the future.

Cause of white flakes

There are two primary causes of the formation of white flakes in your hot tub: calcium scale deposits and biofilm.

Calcium scale deposits occur when there’s an excess of calcium in the water, also known as hard water. As calcium accumulates in the water over time, white flakes will start to form.

Biofilm is made up of natural materials shed by those using the hot tub, which is an overgrowth of white water mold. This happens primarily when the hot tub has been unused for a period of time and hasn’t been properly cleaned. The warm and moist nature of a hot tub makes it a prime spot for mold to form, which produces the white flakes.

How to determine which type of flakes you have

Before you can get rid of the white flakes, you have to determine the cause of them. Use a cup or a bowl to take a 4 – 8 ounce water sample with the flakes floating it in. Add 15 – 20 drops of bleach or liquid chlorine to the water and allow it to sit for 30 minutes. If the flakes disappear, they are most likely a biofilm buildup from mold. If the flakes remain, it is probably a result of calcium scale deposits.

Removing and preventing white flakes


If the flakes in your hot tub are from white water mold, you will need to do a full clean and water treatment of the spa to get it back to normal. This includes cleaning the hot tub cover, filters, skimmer and all other elements of your tub. Then you will need to shock the water to kill all bacteria that is remaining.

Once you are finished shocking the tub, drain it completely, wipe everything down and clean it thoroughly. Once the entire tub has been successfully cleaned, you can fill it back up with water.

To prevent the biofilm buildup from happening again, you should clean your hot tub regularly and check and balance the water consistently.

Calcium Scale Deposits

If you’ve determined that calcium scale deposits are the cause of the white flakes in your water, you need to make sure that the pH alkalinity is properly balanced. Calcium scale will begin to form when the pH levels in your water are too high, so you will need to bring those levels down.

You should also use a scale preventer on a regular basis, which will help to break down existing particles and help prevent the problem from occurring again.

If you have any questions about your spa, please don’t hesitate to contact us. And remember, we offer hot tub maintenance packages to help keep your spa in top shape year-round!