New bull snake temp question

[Knucklesam]

So let me start off by saying this is my first snake. I do have experience with feeding and handling them, however. I also have several other reptile and amphibians. I just got a white sided bull snake at Repticon on Saturday and I love her. I'm a little unsure as to whether I need a heat source or not. I keep all my reptiles in the same room and the temperature during the day ranges from 82-85. The temperature in the tank has been around the same, sitting around 85 most of the day. I'm just curious if it matters that there isn't a thermal gradient. I'm just worried if I add heat then it'll be too hot for her.