I have two options sitting at my house right now. I have a 19 gal round utility tub and I have a 30 gal rectangle utility tub. I hear all the talk about it needs to be round, but I am thinking the 11 extra gallons of space would be more important then the shape. It is one of those rubbermaid types that have the round corners and the sides bow out a bit, so its not a perfect rectangle by any means. So which one would be better to build my tank from? I am hoping to build one so I can catch shad on Friday, use them that night and then still have some alive or recently dead for Saturday night.