Alright. Are you using any kind of thermostat to regulate the heat pad? Some of those heat pads can get well up to 120 degrees, which could potentially harm your snake. I use a HydroFarm thermostat to regulate mine, and it seems to be working very well. I keep the heat set at 97 degrees, which keeps the surface temp around 90 degrees.

Does the digital gauge have probes that you can use to measure the hot side and the cool side of the enclosure?
I think the best thing that you could do to regulate the ambient temp is to get a heat lamp with a red bulb, that's what I use for my snake. The red light doesn't disturb the snake and it can be left on 24/7. The only problem with heat lamps is that they can soak up some of the humidity. I personally don't have any problems with this, since I keep a humidifier running in my snake's room. I hope this helps!