I'm glad we have some good math guys around to help us bio guys. Okay then, now lets refigure this. Diffuser is producing 94,000 milligrams of oxygen per hour into 3,870,000 liters (1 million gal). This results in 0.024 mg/L (ppm) of oxygen added to the entire pond per hour. If our low DO pond only had 250,000 gallons of water, DO production would still only be 0.096 mg/L/hr(ppm). As Ted says above, it is not very much above zero. Now we see why Donnie fish were dying. We can also now see when I say "oxygen dissolves slowly or poorly into water", it is true. All that bubbling doesn't do much in itself to add oxygen to the water.
Note the strong water movements of the diffuser are causing the oxygenated water to disperse widely and relatively fast throughout the pond. This is actually counter productive during a fish kill because it causes the oxygenated water to quickly be diluted into water with low DO rather than allow the reoxygenated water to stay in one smallish area to act as a DO refuge to fish.
