MN,
What is the goal? If you talk to vertex and other diffuser manufacturers, they all have charted how much O2 their diffusers add to the water for a given CFM/depth. Are you trying to see something different. Please let us know.
Also. the fish will be consuming O2, how are you going to account for their usage?
Finally, I assume the BOW will be frozen over, or will there be water to air contact?
