The Reef Octopus CR140 Calcium Reactor is designed to maintain or increase calcium and alkalinity levels in saltwater aquariums without the need for constant manual adjustments. This reactor features a reverse flow water current that maximizes contact time between water and CO2, ensuring efficient dissolution of aragonite media into essential elements. The system includes PH probe holders for monitoring pH levels within the reactor chamber and built-in bubble counters to monitor CO2 drip rates accurately. Ideal for aquarists managing reef tanks ranging from 100 to 200 gallons with varying calcium demand levels, this calcium reactor is a reliable solution for maintaining optimal water chemistry.