The E.S.V. B-Ionic Calcium Buffer is the original, unique, easy to use, two-component liquid supplement system. When using equal volumes of each component, the aquarist can easily maintain calcium and alkalinity levels with no mixing of powders, disruption of ionic balance, or addition of organic chemicals. In addition to supplying highly concentrated calcium and carbonate alkalinity required for calcification, B-Ionic Calcium Buffer System also provides all other important major, minor, and trace elements in the proper ratios to duplicate the composition of synthetic seawater. As a result, the B-Ionic Calcium Buffer System will help restore inorganic ions lost from protein skimming and help maintain the ionic balance of the aquarium water. This size is 32 oz in total. Each of the bottles is 16 oz.