Bill I have never given much credit to the bubbles giving much oxygen in a pond (large water)situation,I know the number is higher than zero but would still be very low and close to zero.It would also depend on the exact diffuser size,configuration and cfm imput and depth.Im sure waste water diffusers going for high OTR's would be tested in this manner.Ill try get a better answer tommorow.Lifting ability seems to be more of a sought after fearture even though the more lifting capability the more 02 should come into play from bubbles. Let me see what I can find as its a great question and Im not giving a very good answer tonight as its been a long day.
