Thanks for the tips! The barn is actually substantially lower than the pond, so I will need the condensate to drain back toward the barn.
I have used an aeration system about three weeks and currently waiting for spring to do the final installation (stuff back in boxes right now). So I am not an expert by any means.
One solution to the barn being lower would be to run your compressor into a small tank. Like say a tire "air bomb" type tank or an old small air compressor tank that the compressor had went kaput would be even better (has multiple inlets and often a drain). Anything safe holding 10 psi would be safe. On the bottom of this tank have a drain where you could manually drain off condensation a couple times a winter. Run the air from the compressor in the top and the air out to the diffuser from another port. This would allow the water to condense and settle in the tank before the air reaches the line going to the diffuser.
You could also make something out of PVC pipe (unsafe for higher pressures but 10 psi not much danger). You could also buy a commercial air line drier like used for paint guns and plasma cutters. Lots of possibilities. Just get the air dry. The aeration people might even make something specific for the purpose I am not aware of.
Then make sure the line drains back to this tank with no dips to the point where the line goes down hill to the pond. Let the condensation from the lines come back to the tank instead of the pond.
