Hello and welcome to FF! As Jack mentioned, T8s (and all fluorescents) are inefficient heat producers. Depending on the enclosure type, to bring up the temperature to 30C during day (can drop 5-6C at night) will require lots of heat. That heat pad under the tank can create you a problem. Sometimes White's will bury (i.e. when stressed) and frog could get burned if it does so near the pad.

My first choice would be a ceramic heat emitter (around 100-150W) in a Fluker's Dome with dimmer. If using another dome, will need either a rheostat (manual) or thermostat (auto) to control the heat output. If an emitter is not available, second choice would be a red bulb because you will have to run day and night. Either solution will dry the air in enclosure, so will need to spray more to achieve 50-65% humidity. Good luck !