Yes there is going to be a overflow box, the box will go from the top of the tank to the bottom. with a standpipe. It is going to be a 1" to 1-1/2" hole, If I put it about 3" from the bottom in the middle of the tank on the back would that be ok? I just don't want this thing to brake, it's not that I care about the tank but I don't want 20 gallons of water on my floor.