Well obviously depends on how fast your water is going to your sump lol. What are you using for an overflow? Usually if you buy an overflow box they are rated for so many gph
. I built a PVC
overflow so I just had to kind of guess.. I had a pump laying around from a while ago and I think with the head pressure it pumps around 500gph.. My overflow couldn't actually keep up with, so
I had to put a ball valve on the return.
I should not that I'm kind of just experimenting with this whole trash can thing.. My biggest concern right now is keeping it clean, so far haven't had any problems.