I have a question about this. I am currently heating from the back and it seems to be working fine but there is no real "belly heat". Given what I have available right now in my rack I'm wondering what others thought about this: Rather than running flexwatt under one end of the tubs (2 tubs wide in rack). Is there any reason I shouldn't run that peice of flexwatt along the bottom *inbetween the two tubs? I have just 3" flexwatt and it keeps the tubs warm...but its cranked up there. So I'm thinking if I move it inbetween the tubs along the floor of each shelf it may be more beneficial/efficient?