ESV B-Ionic Calcium Buffer System (2 part)Maintaining calcium and alkalinity levels shouldn't be complicated. Simplify with the original easy to use ionically balanced 2 part buffer system. It's an economical alternative to a calcium reactor, and when used in equal parts, 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