Microbe-Lift Calcium Concentrate is a newly developed proprietary formulation that will enhance the growth of hard tube worms snails clams pink and green algae as well as helping to maintain a proper pH. Calcium Concentrate (Plus Buffer) is bio- available and will not form chalk like some powdered calcium formulations. Calcium is an important element for stony corals and clams. Corals extract calcium from the water and use it to build their skeletons. Directions... Add 1-2 capfuls (7-14 ml.) per 50 gal. (189 L.) 1-2 times per week. Each 7 ml. capful restores 3.5 mg./L. (ppm) of Calcium. 16oz/473ml treats 2360 gal (8920 litres) **PLEASE NOTE. ALL MICROBE-LIFT PRODUCT INSTRUCTIONS ARE GIVEN IN U.S GALLONS** 1 U.S GALLON = 3.78 LITRES 1 IMPERIAL GALLON = 4.54 LITRES.