What flow rate/range for CO2 into a vertical tube?

[alsetn]

I am building my own vertical tube reactor with an air diffuser stone. I wish to add CO2 to the air line through a flow gauge. If 1 tube contains 10 liters, what is a good flow rate/range for the CO2 in cc/minute or other measurement? Should it be fine tuned to maintain a certain pH?

[conjre]

This information will totally depend on the chemical composition of the liquid you are dissolving into as well as the species of algae present. Different algae species absorb CO2 differently under different conditions. However to answer your last question, yes KH and pH should be monitored in order to make the most efficient reactor when adding CO2 concentrations higher than that of atmosphere.