Protect is a granular product that contains the exoskeletons of diatoms, out of the ocean. It is 75 – 80% raw calcium, and very dissolvable in hot water. The name ‘Protect’ tells the customer that this product helps ‘protect’ hot tub equipment and parts by ensuring that the calcium hardness of their hot tub water is in the correct range. Keeping the calcium level in range prevents corrosion of metal equipment and parts. The correct Calcium Hardness range from 150 – 200 ppm will prevent corrosion (low CH) or calcium scale (high CH).