I'm a new owner with a new baby pastel, and I don't know how to raise the cool side of the tank past 70.In the 15g tank, I've got a medium sized Exo Terra heat mat underneath, and a 100w Red light with a dimmer switch above that. That was on pretty much all night and when I measured again this morning the hot side is 90-95 while the cool side of the tank is still just 70. All my windows were shut and my heat was on so it wouldn't get to like 60 in my house. What am I doing wrong?