Reef Octo CR-140 Calcium ReactorA calcium reactor is essentially a chamber full of Aragonite which is natural form of carbonate mineral or commonly known as crushed hard corals. Aquarium water is circulated through this chamber along with carbon dioxide (CO2). The CO2 lowers the pH in the chamber to an acidic level which dissolves the carbonate minerals into the aquarium water. In addition to dissolving the carbonate minerals, this process also dissolves nearly all the minerals and