Calcium and strontium are utilized by corals, other calcareous invertebrates and seaweed. Iodine and molybdenum are essential for the cell processes of the aquarium inhabitants. These elements are used up faster than can be compensated by partial water changes. Calcium +3 is the only formulated calcium replenisher which combines strontium, molybdenum and iodine in a unique manner so that no cation or anion displacement occurs when added to the aquarium.This formula will promote the grwoth of hard and soft corals and other invertebrates.