How to Increase Calcium Hardness in Pool

As a pool owner, I know it’s essential to maintain the right balance of chemicals in the water to keep it healthy and safe for swimming. One crucial chemical balance to pay attention to is calcium hardness, measured in parts per million (PPM).

Trust me, neglecting this chemical balance can cause major headaches down the line, including corrosion and scaling, which can be costly and frustrating to fix. So, let’s dive in and explore how to increase calcium hardness in Pool like a pro!

Summary: Too little calcium hardness can lead to corrosion, etching, and pitting of pool surfaces, while too much can cause scaling and damage to Pool’s plumbing and equipment.

How to Increase Calcium Hardness in Pool?

Calcium hardness refers to the level of dissolved calcium ions present in the pool water, and if it’s too low or too high, it can cause a range of issues. Therefore, I’ve compiled a detailed, easy-to-follow guide for maintaining a balanced calcium hardness level in your Pool.

1. Dip the Test Strip

The first step to increasing calcium hardness in a pool is to use a test strip to measure the calcium hardness. To do this, submerge the test strip into the Pool for 10 seconds and then remove it.

2. Read the Results

Once the test strip has been removed, compare the strip’s color to the accompanying color chart. This will give you an indication of the calcium hardness level in the Pool.

3. Measure Calcium Chloride

After determining the calcium hardness level, you must measure the amount of calcium chloride to add to the Pool to increase the calcium hardness.

Generally, the amount of calcium chloride required can be determined by subtracting the current calcium hardness level from the desired level.

4. Mix the Solution

Once you have determined the amount of calcium chloride needed, mix the solution. To do this, dissolve the amount of calcium chloride in a bucket of water and stir until it is completely dissolved.

5. Pour the Solution

After mixing the solution thoroughly, slowly pour it into the deepest part of the Pool. It is important to pour it slowly and evenly, so the calcium chloride is distributed throughout the Pool.

Now gradually walk around it, flowing in the mixture until it is all gone. After that, turn on the pool filter and let it run for at least six hours.

6. Recheck the Hardness

After completing this process, recheck the Calcium hardness the next day. Assuming the level is correct, check the chlorine and alkalinity levels, and adjust them if needed. Return the pool filter to its regular operating schedule.

How to Increase Calcium Hardness in Hot Tub?

When the Calcium level goes down in the Hot tub, it will increase the risk of equipment corrosion. This includes the jets, the heating elements, and even part of the shell itself.

How to Increase Calcium Hardness in Hot Tub

However, too-soft water can also result in hot-tub foam, which shows that the Calcium hardness level is too low, and you will have to fix these issues. Balance water must range between 175 parts per million (ppm) and 250 ppm.

And there is the easiest way to increase the Calcium hardness in the hot tub by adding Calcium to the water. You want to add Calcium chloride, one of the active ingredients in calcium hardness increaser, made especially for hot tubs.

Related Read: How to Lower Pool Water Hardness.

FAQs: How to Increase Calcium Hardness in Pool?

Yes, calcium hardness can affect pH. When the calcium hardness level is too high, it can increase the pH of the water, making it more alkaline and leading to the potential for scaling and other problems. Conversely, when the calcium hardness is too low, the pH of the water can become acidic, which can lead to pipes and other equipment corrosion.

To test the calcium hardness in a pool, you must purchase a test kit with a testing solution and test strips. Follow the instructions on the product packaging to conduct the test and record the results. If the calcium hardness level is too high or too low, you may need to add a calcium hardness increaser or decreaser to the Pool.


Overall, maintaining the right calcium hardness levels in a pool ensures its longevity and health, and swimmers can enjoy crystal-clear water throughout the swimming season. Adding calcium chloride to the water is a suitable solution to increase the calcium hardness in a pool.

Moreover, Following the instructions outlined in the article for increasing calcium hardness, regular pool maintenance, and testing can make pool ownership a pleasant experience with clear and sparkling water.