Ok, so the temperature has dropped into the fifties and sixties here in Jacksonville. As a result, my Pacman Frog's habitat has as well. Last night, I went out and bought a 10 gallon terrarium (because the XL plastic tote wasn't maintaining heat well), but his/her new set up is actually staying around the same temp. (70 to 73 degrees) as his/her old one! I bought the appropriate size tank heater and it's mounted on the side opposite the water dish, so I can't figure out why the habitat isn't heating properly. He/she is buried near the heater and moving, so I know he/she is ok for now - I really need to get the temperature raised though, so what are some suggestions for all you experienced keepers who have braved the winter?

Some side information:

I have my apartment's heater set at 73 degrees.
The terrarium is sitting on a book shelf, which is close to the patio glass door.
Humidity is at 80%.