Sounds really intersting. I will be taking a close look at what you do.
I wonder if you could make it more efficant by recelying the escaping O2 from the REZ.
I asoom that the bubbles that pop at the serface would be almost pure O2.
Just off the top of my head,
The air pumps are put into a sealed box that you can pump pure o2 into, the air pumps then pump this air into the rez. There would need to be a return pipe going from the top of the rez back up to the box.
The rez would need to be well sealed too. That way you save o2 and are not pumping 02 into the room, that would make it easyer to full the room with Co2.
At some piont there would need to be air taken out of the system, some sort of valve on a timer.
Of course it would just be simpler to have the pipe in the top of the rez just venting out of the room.
Might work?