Seachem Reef Calcium is a concentrated (50,000 mg/L) bioavailable polygluconate complexed calcium intended to maintain calcium in the reef aquarium without altering pH. Reef Calcium may be used alone to maintain calcium but will provide enhanced levels of coral growth when used in conjunction with an ionic calcium supplement (such as Reef Complete). Reef Calcium is intended to maintain calcium levels; if calcium becomes seriously depleted one should either perform a water change or use an ionic calcium supplement to restore the depleted level of calcium.
Use one capful for every 20 gallons twice a week. The entire 500 ml bottle will treat 2,000 gallons.
Use a calcium test kit to measure your calcium