Soft water refers to water with a low level of calcium in it (<150ppm), while hard water is the opposite with a high level of calcium in it (generally >250ppm). Soft water can negatively affect your hot tub’s plumbing system and other equipment.

Read our article below to know more about the problems relating to soft water in hot tubs.

This post may have affiliate links, which means I may receive commissions if you choose to purchase through links / provide (at no extra cost to you). As an Amazon Associate, I earn from qualifying purchases. Please read my disclaimer for additional details.

Hard water and soft water in hot tubs

Hard water and soft water are two common definitions of hot tub users.

When your hot tub water has a high level of calcium in it, it is called “hard water”. Too much calcium in water can lead to scale deposits built up in your hot tub pipes and equipment. Another possible effect is cloudy water.

On the other hand, soft water has a low level of calcium in it. Potential negative impacts of soft water on your hot tub include corroding the hot tub’s soft or shiny areas, and foaming issues.

The ideal calcium hardness that your hot tub should have is between 180ppm and 200ppm, so the problems associated with soft and hard water would not occur.

Is it good to use soft water in hot tubs?

It is definitely not.

If you allow the calcium levels to drop too low (under 150 ppm), there is a risk of your hot tub equipment including the jets, the heating element, and the tub shell, etc. corroding.

Because the damage caused by soft water cannot be undone, it’s important to make sure that not to let the calcium hardness dropping significantly lower than 150ppm.

Moreover, too little calcium in a hot tub can lead to foamy water which is another problem to solve.

How to know your hot tub water is soft?

hot tub soft water

There are three methods for you to test whether your hot tub has soft water.

The first option is using hot tub test strips which are the fastest and easiest method to test hot tub water. You just need to pay attention to use the kind of strips that measure the water’s total hardness.

Secondly, liquid test kits are test strips that are slightly fancier and require a little more effort, but their results are sometimes more reliable. Similar to the first option, ensure that the kit that you use checks for calcium level or total hardness.

Lastly, stores selling hot tubs and their equipment should provide you with a water test. We suggest getting the water checked by a specialist no less than twice per year.

At minimum once per week, our recommendation is checking for calcium or just testing the hot tub water in general.

How to harden hot tub soft water?

If the problems caused by soft water are not treated, the damage to your hot tub can be permanent. Therefore, you will have to raise the calcium level of your hot tub to at least 180 ppm by using calcium hardness increasers, like the SpaGuard Calcium Hardness Increaser, my favorite one.

Failing to treat the soft water can lead to the erosion of your hot tub’s ground tile, plaster surfaces, or acrylic shell. Other effects can be creating pits on its floor, walls, concrete surfaces as well as its deck.

It’s recommended to check your hot tub’s calcium hardness on a regular basis. The ideal range of calcium levels to avoid problems related to soft & hard water is between 180 ppm and 200ppm.

What to do with hard water?

hard water

Scale deposits will form in your hot tub pipes and equipment if the calcium level in the water is too high (over 250 ppm). Another possible negative impact is water cloudiness.

Therefore, it’s also not ideal to use hard water for your hot tub, and treatment is required. Below are some solutions that you can adopt to fix these problems.

  • Installing a whole-house filtration system (but you need to ensure that the system also includes the water from your hot tub hose).
  • Using a system that softens water to decrease the calcium hardness in your hot tub.
  • Filtering the calcium, which is ideal for water with extremely high calcium levels. This method allows you to accumulate calcium through CalTreat, which is a pool chemical, into a bigger particle that can be removed by your filter system. It takes from 7 to 10 days for this process to work, but it can reduce the calcium level to 200ppm. If you have extremely hard water, this is the best choice.
  • Using a calcium reducer for your hot tub. You can treat your hot tub’s hard water with a chemical that keeps calcium as well as other minerals dissolved and thus regulates them. After following the instructions for the first time, you can repeat the process weekly to weekly treat the water of your hot tub. The chemical can also be used to remove existing scale deposits.

Should you use a water softener for your hot tubs?

Generally, you shouldn’t add any salt (particularly Epsom sales or bath salts). However, if your hot tub water is extremely hard, it’s natural to wonder whether you should use a water softener for hot tub to reduce the calcium level.

One of the problems that you may face after using a water softener is the slow pace that salt takes to disintegrate.

Specifically, salt disintegration can take several weeks or months, so during that period, you can get annoyed by the salt chunks at the bottom of the hot tub whenever you use it.

Final words

Our article has given a clear “No” answer to your question of “Can you use soft water in hot tubs?”.

We have also explained the difference between hard and soft water along with their negative impacts on your hot tubs. Moreover, we have also revealed how to check whether your hot tub water is soft, how to soften water in a hot tub, or how to harden it.

If you have any questions relating to this issue, please leave comments in the box below. We will assist you right away!

Leave a Comment