For those of you who use tanks, do you use an aquarium background or poster board to cover the back and ends? I read on here (and on other forums,) about covering them for a sense of security and some heat retention. I though to use some sheets of craft foam, that should help insulate even better. I don't keep my thermostat very high in the winter, only 69 degrees! I wonder if this would help in keeping the inside tank temps up? I'm getting a UTH for the 20L, and I have a light fixture I could use if needed. I used 25w night bulbs with the gecko, he doesn't like the bright light! Now he's in a smaller setup with a UTH and doesn't need (or want) any light!