I have reflectix on the back 3 sides of my tank for insulation. The entire top of the wire mesh is covered with foil except for where the CHE/dome are. I don't remember the dome size, but I know my CHE is 100 watt (I have a 40 gallon tank, though). Hot side stays at 90°, warm side at 78-80°. I have the CHE on the hot side only. Ambient temp in the room is usually about 70°.

Sent from my SM-G920P using Tapatalk