One Vertex diffuser will move 1150 GPM at 6 foot deep with 1 CFM of air flow ...
It's fascinating how 7.48 GPM of air can move 1150 GPM of water. This had me wondering how but the 1500 GPM isn't all that much power when the water moves slowly and equates to less than the horsepower of the compressor.
Amazing how much leverage their is between air volumes and water volumes. Had me wondering if someone might create a stream on fairly flat land by terminating the end of the BOW next to the start. Just need some way to connect them with a large duct and use diffusers to lift the water through the duct on one side.
Under gravel aquarium filters use this method to move water from underneath the gravel up to the surface. If you have ever seen an aquarium where the water level had gotten low, the bubbler tubes in the back can push water up and inch or two above the water surface and it spills back in to the tank.
Your concept of the circular stream would work if there was a pit at the end of the stream that was deep enough to allow the bubbler tube to build up enough water velocity to carry the water up past the surface to the beginning of the stream. I suspect, however, that is it more efficient and/or practical to use a centrifugal pump for this purpose as the flows desired for an aesthetically pleasing stream would demand a pretty good size pit, large bubbler tube/s, and the air pump to drive it. But it could be done.
