Reptile & Amphibian Forums

I currently keep my ret tail in a2.5 by 5 foot upright home built enclosure. I have dirt and then coconut husk for substrate as well as lots of branches etc. the heating is from the top down so it is in the middle around 32 on the bottom about 26 (this is going to change as the tank is near an open window and we will just close it. we live in calgary and is is getting warmer, like 5C during the day and have been opening it)and at the top around 36. at night I turn the daylight off and it drops about 3-4 degrees. this is where the concern is. the 26 should be like 29 but, the humidity has been dropping quite abit and I have a plastic cat litter container filled with water on the bottom to help with humidity. Has anyone ever used the under tank heater by zoomed on plastic or on wood, as that is what the enclosure is build out of, and had anyproblems. I don't need to wake up in the middle of the night to smoke alarms or worse. I mist on a regular basis but, don't want to soak the enclosure. I thought by heating the water it would warm the bottom of the tank a bit and add humidity but, will look at other alternatives that I know of. I just happen to have a spare under tank heater.
thanx for any help anyone has

just going to get another heat lamp and build a box in the enclosure. better safe than sorry