First or all if you are using a UTH it needs to be monitored by a thermostat. If it's not I would unplug it until you get one. If it should fail you wont know it, and it could heat up to over 130 degrees and kill your snake. Since you have such an odd tank shape you may need to have 2 100w lamps on one end for an adequate hot side or one 150w and one on the cool end. Also I recommend using red lamps 24hrs. In my experience they just put out the best heat. After you purchase your Accurite it doesn't matter which end you put it on as long as the probe is put on the other end and you can tell temps across the board. I would put the unit right under the hot side lamps and the probe on the other side. Those little pet store analog gauges seldom work very long and are unreliable in general. Digital is the way to go. Hope this helps