Advertisement That's obviously from a mat kept on the underside of the enclosure. It could also be from a lamp underneath the enclosure and at another enclosure below that one. My lamp is about 6 inches above. The heat from the red bulb and the ceramic heater are pretty much the same, just easier to see from red light. No inverts, spiders scorpions etc should be kept with an element under them. In nature, the sun shines down. Another reason why you measure humidity is to prevent the animal from dehydrating. You can't see humidity by looking at it, with the exception of condensation. Keep it the same as the natural habitat where they are from.