I bought my first ball(spider) today at the NARBC in Tinley Park. I also bought the Repti-Temp 500r. I placed the probe of the thermometer on top of the glass where the heat pad stuck to and the probe of the Repti-Temp hanging inside the terrarium, I set the Repti-Temp to the lowest setting and the temp based from the thermometer is 111F. What did I do wrong?