ball pythons need the UTH for belly heat, since they stay close to the ground, you can use bulbs as well but that is more for basking spots and to keep up ambient temps in the tank, I've noticed that if you do use a over head bulb, don't use to high of a wattage specially in a 10 gallon, it just gets to hot. you can always buy a temp gun (approx $20) to measure the different temps.