The 35 Gallon mark I have the over flow set to is perfect.. actually.. when loading up on Bunker.. you happy with 12 fish or so. (well at least I am).
I don't run the wash down pump all the time. and actually I think the fish would be fine if I just dumped a couple gallons of fresh water in there every 10 minutes or so..
This is always an option.. but the tank it self.. The best thing I did for the bass season
I'm sure a pump over the side will work fine when not under way.