Different hot spot readings in rack

I built a small rack for myself to house a only a few BPs right now. I have flex watt zig zagging throughout the rack. I used foil tape to secure the probe on top of a piece of tub I cut out, which is secured on top of the flex watt. I placed all that on the bottom shelf of the rack. But right now the tub on the top shelf is reading 94, and the tub on the middle shelf is reading about 88. I tried placing the probe on the middle shelf, but the tub on that shelfs temp was way too low. Any suggestions?
Thanks

I'd just keep moving the probe around until you find the right spot for it! Its what I had to do when I built my first rack, I moved it like 7 times before I got consistent temps throughout. Also I just tape the probe directly to the heattape, and I use electrical tape for that as aluminum foil tape I've heard can insulate the probe so it will hold the heat in and make the hot spot inside the tub fluctuate drastically.

Thanks, thats what I figured Id have to do. Haha Ill keep trying