How to Raise or Lower Water Hardness (Calcium) in your Hot Tub

Balancing Hardness is one of the vital components of keeping a safe and healthy Hot Tub, Lowering and Raising calcium hardness is vitally important in your hot tub, Letting it get to low or to high can wreak havoc with your water chemistry and can badly damage your Hot Tub and it's components. 

While your water does need some calcium to keep your pH levels balanced, having high levels left unchecked can leave scaling and buildup that is difficult to remove and cause irritation to the skin and eyes of its bathers. 

Calcium levels are different depending where you are located in Canada, some water sources are higher than others. It is a good idea to find this out when you buy your Hot Tub, if you do not know, consider asking your local Pool shop. 

In this article we will discuss how to keep your Hardness level balanced, we have some great tips and tricks to do so!

What is Calcium Hardness

Lets start with the basics. Calcium Hardness is the measure of how hard or soft your water is. It measures the amount of dissolved calcium and magnesium. High levels can make the water feel “hard” and low levels can make it feel “soft" if that makes sense. If you take a soak in hard water, you are likely to feel dry and itchy after you get out, soft water may make you feel a little slimy. 

Calcium Hardness is simply the measure of the calcium (or lime) that is present in the water. Keep it at a good level and your skin & components will thank you!

Why is it important to keep your Hardness at a Correct Level

Scaling - High calcium levels can cause scaling and build up on Hot Tub equipment, It causes plumbing issues, filter clogging, and deposits that are really hard to remove once formed. 

Skin & Eye Irritation - As mentioned above, high calcium levels causes a different PH balance, which causes irritation to your skin and to your eyes. 

Corrosion - Metal components of your Hot Tub will suffer from corrosion if the levels of Calcium are too low. 

Water Quality - Water with too much calcium level will start to appear cloudy or murky

What level of Calcium should I maintain in my Hot Tub?

The ideal level of calcium hardness range for a hot tub is between 80-200 ppm. We recommend testing of this every week as with most other levels in your Hot Tub. Most test strips measure Calcium and we offer great products to help rectify if you need.

These ranges are a good guideline because anything above or below means your water is way out of range. If you see it go above or below this, taking immediate action can quickly rectify the situation.

Anything above 1,000 ppm is considered EXTREMELY high.

These levels will always vary slightly, some hot tub manufacturers list their own ranges for specific Hot Tubs. 

Increasing/ Decreasing Hot Tub Calcium Levels

We have products that will raise or lower your calcium level in your Hot Tub. Just add a little to the water and re-test after a while to see where it is at. Add more if need be however you will generally not need too much. 

Low levels of Calcium can be a lot easier to rectify than high levels. Once calcium levels are high, it makes it hard for chemicals to disperse as effectively in your water. Sometimes, if you cannot get the hardness level to come down, it will involve draining the Hot Tub and starting over. 


We really hope that this helps you to battle the calcium in your Hot Tub! Always feel welcome to reach out for advice should you need!