i used to use 24/0 but i did read somewhere that after 20 hrs its just a waste of light and energy ,,not sure if thats true or not ,but i do find that there is no diffrence between 18/6 and and the 24 hr ,:rollj:
i run 24hrs just so the other lights in the room dont disrupt the plant while it is sleeping as my room is not light tight for veg. I think it would be a bad idea to turn the light off for 6-8 hrs and have other lights comming on and off randomly in the room. if it is on 24hrs then there is no worry.
I read a fairly indepth report a few years ago,where they took measurements and recorded all pertinant growth data between 4 or 5 different Light schedules during Veg. and final yield results. 20 on/4off plants had the best growth and best Final yield overall.