I have used both 24/0 and 18/6 with no noticeable difference.

going 24/0 is really helpful if you need help keeping the temps up. and of course going 18/6, having the lights off during the hottest part of the day if you are have heating issues.
CashandPrizes Reviewed by CashandPrizes on . 24/0 >> 18/6 Hello guys, actually i am 24/0 my baby plants 6 Afgani and 3 skunk-thaihaze..... will be a problem backing to 18/6, because actually i am using 45Watts CFL x 3 on 24/0.... i got ready my setup with 400watts hid, here are pics, it is really necesary use the hid now? i know that there is a point in the growing of the plant, that absorb a really high amount of light, anybody knows when is it? about the 4 or 5 of real leaves or something, any overlight before this is waste of energy, i am Rating: 5