Reef Carbonate, 20 L / 5.3 fl. gal. Raises carbonate alkalinity in the reef aquarium A concentrated optimized blend of carbonate and bicarbonate salts designed to restore and maintain alkalinity in the reef aquarium Calcium and carbonates are essential to all coral growth; If either become deficient coral growth will cease followed by rapid decline in coral health Used as directed, it will not deplete magnesium or strontium which usually tend to precipitate with increasing alkalinity 250 milliliters treats 1000 gallons