Thermostat / Multi-Tub Rack / Temp Variation

I am trying to grasp the concept of using a thermostat with one probe to regulate the temps in mutiple tubs in a rack. From what I've read, the tubs at the bottom of the rack are cooler because they're near the floor. The tubs at the top are warmer because heat rises.

Where do you put the probe on a multi-level rack with belly heat?

How much temp variation is there in the tubs at top, middle and bottom?

How is all of this affected when the rack sits in a room where the temps fluctuate 5 to 10 degrees, plus or minus?

Thanks.
JohnNJ

Yes there is a pretty substantial heat gradient from the top to the bottom of the rack. The top can be five or more degrees hotter. In my opinion, it is better to be too cold that it is to be too hot, so I put my probe near the top. In a 10 level rack, I would put the probe at level 7. I then use a heat gun to check all of the temps. I make sure that none of the hot spots get over 95F. I try to keep them as close to 92F as possible. The nice thing about thermostats is that they regulate the temp, so if the ambient temp changes the thermostat changes accordingly to keep the temp at the desired level.

You could also get two thermostats to control one rack. You could put one near the top and one near the bottom. This would give your entire rack a closer heat gradient.

Hope this helps.

You place the thermostat probe in the middle and the temp reader probe on the bottom rack and adjust accordingly. It's better to heat the top shelves a few degrees hotter than to have the bottom below temp and risk a RI. Generally anything under 100 won't hurt the snake and I doubt the top would even get anywhere near that hot if tweaked correctly.

So with the variance from top to bottom, you could have a hot spot of 90 on the bottom and 95 on the top. Would you put the bigger snake in the hotter tub or the cooler tub?