So my new (and very first) BP arrived today! Pics will follow tonight when I get home

I'm having some trouble getting my warm side of my tank at just the right temp. I have a ZooMed UTH and a thermostat from Big Apple Herp. Links below to the exact product. I have to keep the thermostat set on about 81 in order for the temp to be 91-92. If I have the thermostat set on 90 (the temp I would like it to be) it kicks up the temp to like 116.

I have the thermostat probe placed between the tank and the UTH and the thermometer (digital) probe placed on the glass where the mat is. Do I have this setup correctly? Could it be why I can't get my temps just right?

UTH: http://www.zoomed.com/db/products/En...I7czoxOiIwIjt9

Thermostat: http://www.bigappleherp.com/BAH-1000-Thermostat

Thermometer: http://www.amazon.com/gp/product/B00...ef=oss_product