Problems with my heat pad

[msubigdawg]

I have an Exo-terra heat pad for my Colombian Red Tail. She is in a rubbermaid container and the problem is the temp is to high. I plugged my heat pad to a reohostat (however you spell it). I put it on low and yet my temps are still over 100 degrees. I put the thermometer under the bedding, ontop of the pad and thats where the temps are reading over 100. Does anybody have any ideas for help. I thought maybe a thermostat would make it work or do you think I will have to buy a different brand of heat pad.