Heat for bioactive tank & misc.

[MnGuy]

Here's the situation: I have two female garter snakes living in a 40-breeder on aspen bedding. The tank is heated with a basking light during the day, and retains proper low temperatures at night with no heating mechanism. (They also have a UVB bulb during the day.)

Previously they were kept on newspaper and I used a heating bad set low at night during the winters because I live in Minnesota. With the paper being so thin, the pad worked great.

Questions:

1/ I want to convert this to a bioactive tank, but how do I heat the tank over night during the winter? Is sticking the heating pad to side of the tank an option? Or, should I create a very shallow dirt area that allows them closer access to the heating pad? I assume the usually recommended depth of dirt will prevent any heat from penetrating to the surface.

2/ I've considered using a ceramic heat emitter at night, but I don't know that there's enough surface area on my screen lid to accommodate an additional light (the basking light is attached using one of those stands and the UVB strip light takes up some space), and I already own two heating pads so that would save money. Thoughts?

3/ Unrelated, but what do you guys do to protect the cords on your rheostat and digital thermometers from getting damaged by the tank hood? I have a Zilla tank with that sliding screen top, and although I arrange the cords to enter through the small built-in holes, I've noticed serious damage to one rheostat cord (had to replace it because the wires became exposed) and see some wear and tear on the thermometer cord.

Is there anything I can do to save my cords?


Thank you.