What kind of bulbs are you guys using? I just ordered a 48x18x21 tank and am now buying the heating stuff on amazon. I already picked a non light ceramic bulb and two dimmable domes. I'd like the second dome to have a bulb with light on the cold side for ambient temperature and day light since my room is also pretty dark during the day. It should be able to reach down the full 21". The domes I have picked out are the "Fluker's Repta-Clamp Lamp 8.5-Inch Ceramic with Dimmable Switch" on amzn.