I prefer 18/6.... it's suggested (not proven to my knowledge) that you get better root growth during dark periods. In addition to that it's not such a shock to the plant when you change from 18/6 to 12/12 as opposed to going from 24/0 to 12/12.

That's my opinion anyway; but either way.. 24/0 and 18/6 are both prove to work. Whichever you use is your own personal preference.

I choose 18/6 just because I'm a cheap ass and I like to save electricity. :thumbsup:
daihashi Reviewed by daihashi on . Lights on 24/7 Im sure there is a post for this but i didnt see it and apologize if there is one Ok so i have my lights on now for 16 hours then off for 8 Is there any problems with switching it to be on for 24(and is 24 hours 2 much do they need darkness) My plants are about 2 weeks old and im using 3 fluro tubs about 2 inches away, i will have a 400watt hps light tomarrow, and plan on switching the fluros for the hps. Rating: 5