Correct, a reactor would be the best method of CO2 diffusion. You will still need to worry about even CO2 distribution, however.I have a 75g tank so, I guess I would need a reactor.
You may find that this may be enough (or not enough). The best thing to do is monitor your plants and/or place a drop checker as far away from the CO2 output as possible to determine whether there is even CO2 distribution.As far as distribution, would it be enouph to have the output of the reactor near the output of my filter return spray bar? That would help to circulate the CO2 infused water. Or, do I need to hook-up a powerhead to the reactor?
Air stones are not as effective as the glass diffusers with the ceramic discs. If you are relying on diffusion (discs), the smaller the bubbles, the better. I believe that the ceramic discs have pore sizes smaller than that of the finest air stone pores.Wood saltwater air 'stones' work. A inch of chopstick stuck in the end of the gas line works too, but I really like the looks of my glass & ceramic diffuser.