The OTR (oxygen transfer rates) published by Kasco are tested in clean water with no oxygen.
The other factors, surface water interface, wind currents, photosynthesis all play a roll along with the aeration.
Those numbers I gave earlier are from my aquaculture days at Aquatic Eco. We needed to know those numbers in a tank that did not have the plant life or the wind generated currents in them so we could correctly size a blower with airstone set ups.
I think you are fine Bruce and are not too close to the edge in an outdoor pond.
The only true way to know where you stand is by performing a BOD test (Biochemical Oxygen Demand). Some call it the Biological oxygen demand.
