Pond Boss Forums AERATION Systems questions When are multiple airstations required?

New re-dug pond in progress, and I am trying to size and shop for an aeration system. Below are sketches and data of the pond at the current water level and also an estimate when (if) the pond raises 3 more feet to full pool.

To measure area, I approximated the pond shape as a semicircle + trapezoid.

To measure volume, I strung two ropes across the pond, AB and CD. At 10 ft intervals along each segment, I measured water depth. I then took the average of the measurements. The deepest hole is not in the center of the pond but biased to one end.

So, my questions are:

1. How many airstations are needed? I know about the rule of thumb calculation of 1 to 2 volume turnovers per day. This requires the volume of water lift created by the diffusers. Only Vertex seems to offer this data, however. Since the deep hole is not centered, my hunch is that two diffusers are needed - one in the deep hole, and another somewhere along segment AB.

2. Rotary vane or rocking piston? I know this has been discussed many times before, but I'll ask it again. A rotary vane would probably be sufficient since the water depth is less than 18 ft. However, rocking piston compressors seem to be much more popular in the commercial systems that I am browsing through.

Thanks!