BLUE TONGUE SKINKS

I found some BT's in a local pet shop so I ran out and bought them in a hurry so I was scrambling last night to get my 90 gal tank hot enough, especially with the brick of expandable stuff (coconut fiber?) being wet and cold. I ran to Walmart at 11pm and bought a ceramic dome light, a digital probe thermometer with humidity, and a 200 watt bulb. I got a good hot spot in the mid to high 90's. It got pretty cold last night and I've got the air/heat off with the windows open and it dropped to under 60 in my house so I went ahead and just left the heat lamp on all night since the substrate was still damp. I'm glad I did because I woke up and it is freezing cold in my house and in the cold side of his tank it is 59 degrees. I'm pretty sure I'm going to have to do something to provide constant and or overnight heat to the middle and or cold side of the tank. Years ago with my bearded dragons in the same tank and I had an undertank heater and later I got a ceramic heater and it all worked well, I also had that set up in a cold basement. It has been quite a while but I remember that I tinkered with it for a while until I felt comfortable with the ambitent temp not dropping too much. However I'm concerned that with this guy burrowing so much that he might sit right on top of an undertank heater and get burned?

I'm debating what source and or combo of sources of heat for constant or overnight heat to keep the cold side and or overnight temp at least in the 70's? Ceramic heater? Night light? Undertank heater?

If it drops under 60 at night then yes you need to use a overnight heat, i would suggest either a ceramic heater or a designed night globe.

Before I had my snakes in racks I had one burn himself on an undertank heater when he burrowed under the substrate. I would suggest a thermostat if you are going to go that route. Get yourself a temp gun too, so you can monitor temps a bit more accurately. Ceramic heaters and night bulbs work well too, but you don't want it to get too hot at night. I do not use nighttime heating unless I feel one of them has had something to eat a little too late, then I will turn on the night bulb.