Expert Verified Updated: March 2026

Calcium Hardness Increase per PPM Calculator

Calculate exactly how much calcium chloride you need per ppm increase in your pool. Prevent plaster damage and corrosion.

Quick Conclusion
To raise Calcium Hardness by 1 ppm in 10,000 gallons, you need 0.125 lbs (2 oz) of Calcium Chloride. Target 250-450 ppm for plaster pools.

Technical Comparison

SurfaceCH RangeRisk
Plaster250-450Etching
Vinyl175-225Metal Corrosion
Calcium Hardness (CH) is the measure of dissolved minerals in your water. If it is too low, the water becomes corrosive and will etch your pool's plaster and grout to satisfy its 'hunger' for calcium. This lead to permanent surface damage.

Actionable Steps

1. Test current CH. 2. Calculate dose of Calcium Chloride (77-94%). 3. Pre-dissolve in a bucket of pool water (Caution: exothermic). 4. Pour in deep end. 5. Circulate for 24 hours.

Pro-Tip

Exothermic Reaction: Calcium Chloride generates heat when mixed with water. Always add chemical to water, and never use your bare hands.

Frequently Asked Questions

Ideal range?

Plaster: 250-450 ppm. Vinyl/Fiberglass: 175-225 ppm.

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