For the past month or so I've had my calcium reactor going on our big tank in the lab (something like 350 gallons total system volume). It seems like it is going through CO2 much too fast. If you run a calcium reactor on a similarly sized system (or on any system), how quickly do your CO2 cylinders get emptied? ---- Prior to running the calcium reactor, we were needing to add about a half liter each of each part of the BRS two-part supplements (calcium chloride and soda ash), each day, to keep up with uptake by the system. For about a month I've been running the calcium reactor (a reactor built by Bill Wann) with a target pH of 6.5 for inside the reactor (controlled by a pH controller and solenoid valve). We have a central CO2 system in our department, with two LARGE (like, at least 4 feet tall) CO2 cylinders and CO2 lines going out to various labs. In no more than a month, both of our large CO2 tanks have been emptied (they were full at the start). And the only thing using the CO2 this past month was my calcium reactor. This depletion of the CO2 seems far too fast. There were some suspicions of problems this past summer as well when the CO2 was being used in a tissue culture incubator in another lab. We are suspecting some sort of leak somewhere in our CO2 system.