I have a 65w flood light and i use a basking rock. the bulb sets 11'' from the substrate and rock, but barely reaches and stays 90. I have a dimmer switch on it and it is all the way up. So, I temporarily put in a regular incandescent bullb that is 50 - 150. At 150w it maintains temp around 96 at 11''. I feel that the regular bulb just acts a spot bulb and doesnt really spread the heat out much. Any suggestions or is this bulb okay? my concern is that I have read in previous posts that MVB and spot bulbs are harsh on the carapace and cause pyramiding.