Got a pvc rack few days ago, just testing temps right now before I put any snakes in there. The temps are a bit weird though..

Its a 2 tub wide, 4 shelf rack (so 8 hatchling tubs in total). Right now the thermostat is set to 104.5 and I am achieving the following temps:

Top row:
Hot side 87-89
Cool side 75-77

Second highest row:
Hot side 90-93
Cool side 76-77

Third row:
Hot side 89-90
Cool side 76-77

Fourth row: no tubs as of yet, need to be replaced since they were broken during shipment.

Dont worry about the cool side being too cool. I plan to run a space heater at 80F a few times daily, and keep the door closed to keep the heat in. The ambient (cool) side temps should be up to 78-80 at all times.

What I am worried about is the hot side temps. How come the second row is so much hotter than the other two rows? And how come the top row is the coldest when in theory, heat rises?

Any input will help. The hot side temps are just the hottest temps I measured with my temp gun, the ambient around the warm side is around 83-86~ Just as a reference, my rack was built with the same plans as the RBI racks. Thanks