most dont mutilate the tub just get another one and cut a piece out of it, and use that one for storage etc... that's the way i plan on doing it with my rack just gotta figure if i wanna go thermostat or rheostat, i really dont ever have a problem with rheostats room temp really doesn't mean anything if it's providing the same amount of heat to the belly, well it's going to keep it that temp consistantly unless there's a massive drop in temp, which usually doesn't happen in a house.