So, the spot temps I have are 91-94 on the warm side, 80-82 on the cooler side.

-Humidity is about 63-65%.
-Daytime ambient air is about 81.
-Night time ambient air is about 78.

The question is: is the night time 78 too cool? I'm working at getting it up, but obviously there's a balance with the temp and humidity.

If I cover the tank more, (less ventilation) the humidity gets 85-90%, but the night time ambient temps are up to 81-82. To keep it at 60-70% humidity, ambient at night drops.

It's a 20 gallon glass cage, resides in the basement. The basement is conditioned with our furnace, but you know how well furnaces heat basements without zoning...anyway. I'm just wondering if the 78 deg. is a problem through the night.

I plan on insulating the outside back and sides of the tank to help with heat loss -- unless the 78 night time is ok.