Calcium water is a solution you make with water and the monocalcium phosphate powder (food-grade rock mineral source) that comes in its own packet with every purchase of Pomona’s Pectin. The Pomona’s Pectin directions tell you how to make calcium water with the calcium powder. Pomona’s Pectin recipes call for calcium water because the pectin is activated by calcium, not by sugar. For more information about calcium water, please visit the FAQ page, Section 2, of the Pomona’s Pectin website.