I think I see what you’re saying. I attached a pic of the shape I am thinking in this post: http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=486287
I was thinking of running twenty 3 inch pvc pipes from one side of the horseshoe to the other, each with a 1 inch airline attached 3 feet below water level. Apparently this is the most efficient way to move the most water (vs bigger diameter pipes, or piping the air further underwater)
What do you think? Do you know of anyone who has done something similar that I can learn from?