Yeah i had the same problem when i got mine a few weeks ago. You turn it everything off, mine is on timers so everything goes off at 8pm and back on at 8am you just want to switch everything off and they will immediatly go to sleep. They tend to bury them selves which helps them stay warm but also the temp would rarely ever drop below 60-70 depending where you are. If your from scotland then i'm not to sure but in England your be fine. Hope this helps
Just put a themometre in the centre of the tank at the back and just check on the temp before you go to bed. That's what i do and she is fine
They are good fun you will love them. Enjoy!