Is it a CHE or just a regular bulb?
I'm asking cuz I have my CHE on 24/7 and the basking bulb is on 13 hours a day set on a timer switch which is inexpensive I payed like $10 for it at walmart and super simple to use and it repeats the cycle daily
Between 12 and 14 hours in most cases. The only time I would go below 12 is if I was cycling a hibernating species and preparing them to go down for their winter slumber. I would use the 14 hour setting for a hibernating species that is awake during the middle of their active period. For most tropical species, most of the time, I like 12 hours.
make sure that lamp fixture has a porcelain socket base or that CHE may melt it if left on constantly, ask for one that can handle 300/200wats home depot should sell them and get a larger dome for CHE 10" is my minimum and i prefer dimmable ones. i go lights gofor 14-16 hrs