usually when the lights go off is when the humidity rises,so leaving the fan going will help keep air circulating to keep mold away.also if you are worried just put a peice of black tape over the light
mscaboo Reviewed by mscaboo on . Quick Flowering Question Ok 2 Questions. I just started flowering about 5 days ago. #1. Should i leave the fan turned on while they are in darkness? #2. When you say "complete" darkness, will the red LED from the fan be an issue? I've tested any light leaks and there are none....except for that little red light from the fan which really doesn't illuminate anything, BUT....its not "complete darkness" like you guys say. Rating: 5