Greg. Yes you can use this info in your promo but please give me credit for creating it at the article's end. I also have quite a bit of similar aerator information in the aerator section. It seems I have to repeat this same stuff often.
You are correct about fountains in small, shallow or medium depth waters. Key point is small & shallow. They are okay there for bottom mixing. The pond's exposure to wind has a limiting factor here. Fountains in smaller shallower ponds can mix water deep enough and over most of the pond's area/volume so that there is no or minimal, deoxygenated, water volume in the bottom zone. Then when this low volume poor quality water is inverted it cannot degrade the upper layers ENOUGH to cause problems UNLESS there are other unusual conditons such as cloudy days, heavy aquashade or other oxygen robbing or suppressing conditions occurring at the same time or shortly after the inversion.
As I mentioned above, if there is a turnover/inversion in a larger or deeper pond, an operating fountain can maintain enough oxygen in the vicinity of the splash zone to keep many fish from suffocating.
But here again, why would one want the bottom of a deeper pond to be without oxygen and get septic? I think almost all of those that allow it to happen do not realize it is happening. If they had to be in or exist in that deep deoxygenated water for only one-half minute, I guarantee you it would be corrected if possible. It occurs in many many ponds because the owners do not realize how bad it gets down there and the severe degredation of bottom sediments that occurs. Out of sight; out of mind. If you can't see it then it must not be happening. Everything looks okay, maybe even sort of pristine from on top until fish start gulping for air. One cannot see black sludgey, souppy septic muds and the massive die off of the bottom bugs in the deep sediments. Also if you closely examine the black mud botttom sediments, there are no living invertebraes in that stuff. That should tell you something.
