Calcium Hypochlorite
Calcium hypochlorite is a granular chlorine compound used primarily as pool shock, with approximately 65–73% available chlorine.
Definition
Calcium hypochlorite is a granular chlorine compound used primarily as pool shock, with approximately 65–73% available chlorine.
Typical Values: Available chlorine: 65–73%; Does not add CYA; Adds calcium
In Plain Language
Cal-hypo is the standard granular shock product for pools. It dissolves completely and adds calcium to the water (relevant in areas with already-high hardness). It does not add CYA, making it ideal for breakpoint chlorination and regular shocking. Pre-dissolve in a bucket of water before adding to the pool — never add directly to the skimmer, as it can corrode equipment.
Why It Matters
Cal-hypo is the most effective and economical shock product for regular pool maintenance. Understanding its calcium contribution helps prevent scaling in hard-water areas.
Typical Values
Available chlorine: 65–73%; Does not add CYA; Adds calcium
Last reviewed: 2026-06-01