use for old pump

[Fish]

That's a good point. The only reason that I thought it might be tough as a sump return is that it would be a ton of water for an overflow to handle and a ton of water going through a smaller sump.

I guess in a closed loop you would have to probably split the intake into two pipes, maybe one in each corner, and have a threaded screen in each intake... you're right though, that is a lot of suction to have in one place...