I'm having some trouble with my heat mat. I have it plugged into a Habistat Mat-Stat, but even when the dial is turned to 92, the mat's temperature won't go above 86, so it's not creating a lot of warmth once it gets through the tank and through the substrate. I've had it on and running for a couple of hours and it doesn't seem to be heating up any more than this maximum. How can I fix this? I'm not 100% sure I have the Habistat itself setup correctly because it had a screw dial and it's not very clear which way the arrow is facing.