For any new or prospective snake-buyers, make sure you buy an infrared thermometer (temp gun), it is an important tool for spot checking your temperatures.
I have my bp's tank set up just like in the stickied threads, with digital thermometers each side of the tank, a centrally-located heat lamp w/ dimmer switch (rheostat), and a UTH w/ thermostat under the warm side.
I check the thermometers before going to bed and in the morning, and adjust the heat lamp if necessary (if it's going to be a warmer day, colder night, etc.). Everything always seems fine.
Today, while buying some more clutter for the tank, I noticed that the store had basic infrared thermometers in stock again (~$25 CDN). I had skipped over it when buying my initial gear (figured it was more for the serious harpist), and it slipped my mind after that.
After getting home, I checked out the tank with my new toy. I discovered that except over top of the UTH I had nowhere near as much of a proper temperature gradient as I had thought, based on the thermometers. Though nothing was in a harmful range (low or high), it still does not strike me as a healthy setup for a reptile.
TL;DR - Go buy an infrared thermometer, they're relatively inexpensive and will ensure the best environment for your slithery friend![]()