Calcium Hardness (CH) shows you how hard or soft the water is in your swimming pool.

Increasing CH levels is best done with calcium chloride. Use our calcium hardness calculator to understand how much is needed to increase your CH levels.

Calcium Hardness Calculator



If you don’t know how much water your pool holds, use our calculator for a rough estimate.

Know Your Calcium Hardness Levels

Calcium hardness should be between 250 to 500 ppm for concrete or plaster pools and 100 to 300 ppm for vinyl and fiberglass pools.

While CH is not too important for vinyl (and some may say you don’t even need it), you should at least have some in the water.

When you need large amounts of calcium chloride, add it in increments. The only reliable way to decrease CH levels is to drain and refill with fresh water.

This is why it’s important to have a reliable CH measurement. Using an accurate testing kit can save you time and headaches down the road if you happen to overestimate the readings.

Need a Refresher on Chemistry Readings?

Calcium hardness (CH) is just one of multiple chemistry readings to maintain water balance. Download our handy guide for a quick and easy review of all parameters and chemicals to use.

It Isn’t Hard(ness)!

Staying on top of testing and your calcium hardness levels isn’t overly difficult.

Check CH levels weekly, especially after a storm with heavy rains. Find how much calcium chloride you need to add.

Then, enjoy the pool!