Calcium reactors are used to supply a reef aquarium with a consistent level of calcium. A calcium reactor is a sealed container filled with calcium carbonate media, which is dosed with carbon dioxide (CO2). The CO2 entering the reactor lowers the ph of the water inside of the reactor, which dissolves the media releasing calcium into the water. For a complete calcium reactor set-up one needs a CO2 bottle, CO2 regulator, needle valve, solenoid valve, the reactor itself, pH-monitoring device, and a small feed pump.
