This calculator determines how much calcium chloride to add to increase the calcium hardness (CH) from the current concentration to the desired concentration in ppm. The ideal calcium hardness range for most pools is between 180-220 ppm.
⚠️ Always pre-dissolve calcium chloride in a bucket of water before adding to your pool. Never add directly to skimmers or near pool walls. Adjust for your specific product’s purity and follow label instructions.
The best way to know your pool’s volume is to refer to the original documentation from your pool’s manufacturer or construction plans. Otherwise, you can use our pool volume calculator.
The ideal calcium hardness range for vinyl pools is lower than for plaster pools. CH in vinyl pools is usually kept between 175 to 250 ppm.
Plaster pools need a higher CH in order to keep the plaster from etching and the grout from dissolving. The ideal CH range for a plaster pool is between 200 and 400 ppm. Raising CH too high can lead to scaling.
To sum it up, you want the CH in a plaster pool high enough to keep the water from dissolving the plaster and low enough that calcium does not begin to deposit and build up on the plaster, tile, and grout.