thermostat probe location

no matter how hard i search i cant seem to find where anyone puts the probe for the thermostat in a rack. obviously you dont have a t-stat for each tub so how do you know that every tub in a 20 tub rack is at the exact rite temp. im sure this is something everyone knows but im a noob trying to set up my first rack and it is now the only thing irritating me about the whole thing. thnx in advance.

You secure the probe on the middle shelf right above the flex watt.

As far as your temps you take a reading in each tub with a digital thermometer (a slight differential between top and bottom tub will be normal)

I put mine roughly in the middle of my rack.

It doesn't really matter where you put it though if you have a temp gun. That way you can find a temp that works for all your rows. The top shelf is going to be warmer than the bottom shelf, there really isn't much you can do about that unless you want a thermostat for each row.

If all levels are the same (example: same length/width flexwatt) I tape the probe onto the middle rack directly ON the flexwatt. I read all other temps with an IR gun, which is usually only 1-2 degree difference.

i figured the middle was right but completely forgot about the temp gun. luckily i already have one ordered so i did something right. thnx for the help.