It is impossible to maintain a healthy, vibrant marine aquarium without also maintaining the proper levels of calcium and alkalinity. Fritz RPM Calcium Buffer System allows aquarists to maintain these two critical components in their proper ionic balance. Unlike other similar products, Fritz Calcium Buffer System does not contain unmeasured and unnecessary ions and metals, which unchecked can lead to toxicity in the aquarium. Part 2 is formulated to provide the highest purity calcium, and when used in conjunction with Part 1, along with regular water changes with a high quality salt, will provide the correct ionic balance necessary for healthy and beautiful coral, fish and invertebrates. Guaranteed Analysis: Calcium (min) 55,000 ppm. Ingredients: Deionized water, calcium chloride