I like your idea. It might be possible to avoid the use of the air pump by having the compost tea that is pumped up drop into a vortex which would aerate the liquid before it entered the upper part of the system to descend.
"Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has."-Margaret Mead "The only thing worse than being blind, is having sight but no vision."-Helen Keller
You showed up just in time for the waffles! And this tiny ad: