i got one megaray 160 watt 18" from the bottom of the bulb to my basking rock wich is a big black piece of slate about a inch thick and I get 127f basking temp. and 97-99 air temp on hot side and 84-86 on cool side. i also use one of the 10.0 coil uvb lights but being so high it does nothing for uvb for my uro but I basiclly use it just to make the tank brighter and with the megaray I get plenty of uva/uvb. i swear thos are the best bulbs I ever used