Okay the simple question that i have is this: Do plants roots need to be directly on air bubbles in order to breath? Or do the air stones infuse the water with a greater amount of oxygen? If you dont know or never read a research article on this please do not answer. The drawn out story & question is this: I'm now running two reservoirs. Each holds two plants. I have a cheap whisper air pumps. It puts a good amount of air into both rezes but the air stone sits in the middle of the rez between the two plants. It looks fine. However it's not fine if the roots have to sit over the bubbles to keep them from drowning. If air stones infuse the water with oxygen then my setup is fine. If plants only breath the O2 that directly touches then then I'll need to add another airpump. answer needed ASAP. Thanks for any and all assistance.