I agree with the under cage heat assesment. I used to use lights years ago and it was a constant battle maintaining temps, especially in tanks that in my opinion are the absolute worst thing you can put a snake in short of a plastic bag. If you are going to use a light I recommend a vision cage or similar that holds heat. Glass does a very poor job of holding heat, and also screen tops allow all of the heat to go right out the top(as well as humidity). They also allow drafts to pass through, and before you know it you could have a snake with a resp. infection. Also retics tend to be apt to push ALOT, especially if unhappy, under fed, not in adequate space, or because they enjoy it(who really knows) ect. So even if you have enough weight and such to prevent escape, they can still mess there faces up pretty bad quite often. Also then you have to worry about them pushing and breaking teeth which can lead to infections, mouthrot and other awesome things to treat. To me, without coming off like a jerk, I dont think you are ready for a retic if you plan on keeping it in a tank with lights, its not practical and certainly isnt best for the animal, which should be your utmost concern. If you must use a tank they sell products to help insulate the glass, and there are some things you can put on the screen top to prevent rubs, but you cant use those with a light, so it still wouldnt work. If you have the money to spend (which if you are getting a retic I assume you do) I would get a thermostat and some heat tape with a compatible cage(RBI has some that comes ready to plug in to your thermostat) so that you can better control the temperature in the cage and maintain the health of your snake in the long run. I hope you find this information helpful. Also be mindful of having to buy several cages over the course of your retics life, and understand there will be some money and time involved to keep this animal healthy and happy. I wish you luck! Dan M.