Adjust thermostat until temp under substrate is where you want it to be. Naturally you're going to have to set the thermostat higher to achieve the proper temperature in the tubs. But I don't think 3" tape in a 71 degree room is going to cut it. IMO that's too cool for a rack system.
Many racks do not keep a warm enough ambient temp is cool rooms. The heat tape is not going to get the ambient temps to rise so you may want to move it to that warmer room now.
BTW, your snakes don't really want attention and a less travelled area will be perfect for them.
KMG
0.1 BP 1.1 Blood Python 1.0 Brazilian Rainbow Boa 1.0 Aru Green Tree Python
0.1 Emerald Tree Boa 0.1 Dumeril Boa 0.1 Carpet Python 0.1 Central American Boa
0.1 Brooks Kingsnake 0.1 Speckled Kingsnake 1.0 Western Hognose
0.1 Blonde Madagascar Hognose 1.0 Columbian Boa
I just set it up and didn't even set up the thermostat. I don't have any animals in it at the moment. I have the heat tape cranking along and the temp just hit 81 degrees under the mulch.
What is the lowest ambient temp of the tub that is healthy for a ball python? I currently keep mine at 80 degrees with a 90 degree hot spot on the mulch and he is doing great.
I don't want to warehouse them, I want them to get used to me handling them.
I have more heat tape, but I'm thinking it might gradually warm up.