Help with baby bull setup

[Kaianuanu]

So I decided on a baby bull snake and I want to start getting my setup ready, I decided since I already have my two carpet pythons in display setups, I would try to go with a really economical housing for my bull since it won't really be a display animal. Since I will be getting a 2013 baby, I went out and got a 16.5"L x 13"W x 6.5"H 15qt Sterlite tub. I don't have a lot of experience with keeping animals in tubs like this. I can figure out the cage decor, like the water bowl, hides and etcetera, and I'll probably go with aspen or paper towels for the substrate. I also figured I'd melt a row of holes on the sides for ventilation with a soldering iron. However, what I'm not sure about is the best way to heat the cage. I live in Florida and my house usually stays at 80 degrees with a humidity around 40%. Should a simple small heat pad do the trick? Also, I have my fish room which is around 83-84 degrees and has slightly higher humidity which I could also put the in, would I even need heating in there?