I find that black light bulbs are the best i use 100-150 watt bulbs. I tried the heat pad thing and it was not very efficient mainly because my bins are quit large if you had a very small bin it may work better. If you want them to breed well the hotter the better. They do their best between 90-105. I wouldnt go any higher then that. 80 degrees they seem to breed ok but much slower. Hydration is also very important as before mentioned in this thread. And with a light you will need to pay closer attention to moisture then with a pad. The bin tends to become dry faster. But if you have a water cryistal dish then you wont have any problems just add a little more water to the cryistals when they start shrinking and problem solved.