A photoperiod is necessary for frogs. 12 hours day and 12 hours night. A 100 watt does sound a little strong. I suggest maybe a 50 watt. A heat pad i have always found doesnt really keep my frogs warm. As long as the temps dont go too far above the low 80s. I will post a care sheet to give you a little more info.

http://www.frogforum.net/content/whi...-caerulea-121/