Palintest Calcium Hardness photometer tablets give fast, accurate measurement of calcium hardness in pools, spas and process water, over a range of 0 to 500 mg/L CaCO3. Keeping calcium hardness in the right range helps prevent scale build-up and protects pool surfaces and equipment from corrosion. Each pack contains 250 individually foil-sealed tablets for use with Palintest photometers that include the calcium hardness test, such as the Lumiso and Pooltest range.