Several scientific tests have proven that 24 hours of light is ideal for the first 6 weeks or so and then around 20 hours/day after that.
Its been discussed here quite a bit in the past, and links to these tests are posted here somewhere
My plants getting 18+ hours are doing much better than my 12/12 plants
ohh dangg thats craazzy. maybe ill just leave it on all night then for the next few days.