What and how often are you feeding him? How old and big is he? I would suggest placing the probe outside the tank on the heat source, it will take a little tweaking but will be a lot safer for your animal. Measure temps inside the tank with a temp gun, ex. surface temps may be 90* but the t-stat may be set at 101* to maintain 90* in the tank. Definately no tape. The covering of the glass and plants will help if it's a security issue.