It is a closed rack but it is open on the long side so I can fit 2 15 qt tubs side by side as well. If I bump up the warm side it would burn the snake it's currently reading 93 with a temp gun. Its the air temp that I am concerned about it is reading 75 and in the winter it will probrably go down to 70 I want to know if there is a way to bump up the ambient temps with out a plug in radiator.