Calcium reactors are great tools to provide your reef tank with all of the necessary reef building elements like calcium and magnesium, as well as boost the alkalinity of the water. But to get the most out of your reactor without wasting CO2, here are some things you can do. For one, slow the flow through the reactor. Because most calcium reactors use recirculating pumps, the flow rate through the reactor can be quite slow. This allows hobbyists to have the proper pH levels without chewing through a 10lb bottle of CO2 within a month’s time. Additionally, the pH level within the reactor won’t have as large an impact on the overall pH of the aquarium’s water. If you do like to run a really low pH within the reactor, however, the output line can be dripped into a protein skimmer which will help offgas some of that excess CO2.