hello all. I've built a rack out of 3/4 Melamine that is 2'deep x 4'wide x 6'tall.this rack holds 27 32q tubs. I'm using 4 6 foot strips of flexwatt as back heat. I left the bottom shlef empty for storage & also because I don't think that shelf will really stay warm enough being so close to the ground. my problem is that the bottom only gets to about 81 degrees while the top is at 90 degrees. I bought weather stripping & put that on the back of each shelf to try to cut down on the heat rising & it helped a little but I need advice on evenning out the temps. thanx in advance for your help.