I don't see there being a reliable setup with something like this. But that being said, I imaging the best way would be to run pvc
up through the bottom to create an overflow of sorts. The height of the pvc
in the container would determine the water line. You would also have to cover it with some sort of sponge to keep fry from getting sucked in.
Then for the return would require a large amount of pvc
hosing and rig up an extensive system.
Honestly, it's easier and probably cheaper to get a few 10g tanks, sponge filters, and 1 fairly powerful air pump. Not to mention if one bacterial infection takes hold it can wipe out the entire system.