I can see where water in the lines would be a big issue.
The standard recommendation is to make sure all air lines run down hill into the pond so there are no low spots for water to accumulate.
Yeah right. Good luck with that one. Maybe if the pump house if right near waters edge. But at least with my level of skill running a trenching machine and not wanting to get a laser level out and hand level the bottom of the trench, good luck in getting a line that is installed perfectly enough so there are no low spots that will hold water. Putting it below the frost line would cure the freezing problem, but just looks like running an air compressor through the winter is problematic and would require some babysitting.
