All I use are black heat lamps.I take my dog, Misty, out two or three times during the night to pee. It is NEVER totally dark outside at night (I live in the country with no lights). Even when the moon is just a sliver, there is some light at night. A black light is just like moon light. All of my tortoises are sleeping at night. None of them comes out and says, "Hm-m-m ... that lighting makes my substrate look like something I want to eat!" No, they sleep at night, they don't come out and eat or wander.