When I get my male set up in a 20L Im gona have a heat pad with a thermostat, and Im gona put a uv fluorescent on it. I have several fixtures but I will probably use an 18in. There is a lot of unknowns as far as snakes and uvb is concerned. It could be beneficial for breeding, and it could also help snakes fight illnesses. Im thinking the fluorescent bulb won't produce much heat. So It will have controlled belly heat. Providing uv-yes or no? Im also thinking the fluorescent bulb won't dry out the enclosure as much as a regular bulb.