we for a wee one you are really good with a 20 gallon so as not to stress him. I personally use Power Sun bulbs in all my enclosures as they are an all in 1 bulb. I order them from www.petmountain.com as they are half the price of anyone else. I would suggest getting some laminate for the bottom of the aq. (very cheap) and cutting and laying it down. Cleanest thing to use and cheap and easy to clean. When they are little you really want to stay away from sand. Get him a good basking branch and a little hide and a water dish that is not too hard to for him to get out of. You can do all this on the cheap for the hide and the dish...$$ store. A good branch you can get outside. Just cook it at 250 for an hour in the oven. You will also need a cricket enclosure. When little they eat 20% greens and 80% protien. Oh yea.....forgot....I just use a lid to a tupperware container to put greens on. I think that is about it. You may need a red light at night depending on how cold your house gets. At night you don't want to it to get below 70.
When they get bigger it is recommended a 4x2x2 enclsosure for an adult.