The Herpstats are prewired so just hook up your UTH to it and mount the probe. I prefer having the probe in the tank mounted to the floor over the area where the UTH is. Secure the probe down with some clear packing tape. Then you can put newspaper or substrate over the top. Putting it underneath the UTH on the outside means ambient airflow can cool it off and you don't get a good idea what the actual temperature is in the enclosure. So for me.. probe in the enclosure, UTH under the enclosure. Having some risers under the enclosure is a good idea as it helps prevent the heat element from overheating and failure.

Dion Brewington
Owner, Spyder Robotics