The substrate is about an inch and a half in most places. I need to give the whole thing a cleaning in a bit so I'll experiment with having a very thick area where the frogs can go to cool off, and a very thin area (maybe nothing but sphagnum moss) where it will be nice and toasty. If worse comes to worse I'll try a ceramic heater.
I might not get another top though- I propped the little access door on the top open a few centimeters with a pen, and put a weight on top.... Let it sit for about 30 minutes, and all condensation is gone. Temperature is hovering around 65-70, and Humidity is still 50%.
Might have done the trick~
Thanks for the input. I want my frogs to be as happy as can be :]