Hi, I currently have a 10 gallon tank, but I am upgrading to a 20 gallon tank. For the new home for my leopard gecko I would like to know if I should use a UTH or a 100-125 watt red heat bulb or both? Currently I have both a small wear UTH and red heating bulb, but shut the light off at night. Also, I heard to place the UTH on the side of the tank and not the bottom. Please I would like your feedback. Thank you