no do not do 24 hours of dark, people do that to clones they just cut off, it helps with perspiration and helps with shock. i never heard of anyone doing it before flowing. I have heard of people doping 24-72 hours dark before they cut the plant down and i think that has to do with not soaking up and nutes if your using organic. i guess the theroy is with the light off its not growing and using nutes. THe most important reason i say not to do 24 hours of dark is you dont want to shock them and get hermis. keep the same schudule your on and put it to 12/12. watch how much the screen will fill up after you switch it