My options are "it doesn't matter" or the second one, which must imply that it DOES matter, but no choices to indicate which one ??????
Well, seeing as I can't vote for either option then, I'll add my two bits to the commentary without voting.
I'm with Deb: I don't like disturbing the tank inhabitants at night unless it's serious. Sometime fish can get VERY distressed when disturbed at night. I try to avoid even having the room light on after tank lights-out.