[DJ88]

CO2 is inputted into the reactor from a CO2 bottle. Usually it goes through a buble counter of some sort so you can see at what rate it is going into the reactor. You will need to refill this bottle as it empties. The time frame for this will depend on how much you use teh CO2 and how large/small a bottle you have.

Due to the low pH it is more desireable to run the effluent intoa sump where it can mix in an area without corals or anything like that. This is especially important if you are running a higher effluent rate. Say 120ml/min or more. (rough guesstimate). As well running the effluent to your sump allows for you to let any escess CO2 be released by the effluent in your sump rather than in the main tank.