definitely run an airstone in every container, it makes a world of difference :thumbsup: ... I won't pretend to know for sure, but I 'think' the plant gets its CO2 thru the leaves, exclusively ... it 'may' even disrupt the plant's oxygen uptake thru the roots, by displacing the oxygen with CO2 ... TIP: CO2 will only make a positive difference, IF everything else is 'spot-on perfect' (it gives the least amount of improvement, of things you can do) ... since I am in a small (2'x4'x7') cabinet, my bottle of sugar, yeast and water probably emits enough to help a tiny bit ... you won't see BIG differences with CO2 ... :smokin: