Calcium Plus is a highly refined, calcium-rich mineral designed to increase the hardness levels of spa and pool water. A clean, white granule, this product is used when calcium levels are low to increase them. This prevents premature deterioration of spa or pool surfaces, including synthetics and vinyl, as well as unnecessary corrosion of equipment and metal surfaces. Calcium hardness also plays an important role in ensuring that the overall mineral balance is correct, improving comfort, chemical efficiency and maintenance costs.