I vary the time of the moons to try to mimic the moon phase, best I can. 1 week off, 2 weeks couple hours increasing to 1 week on all night. I'm sure people will say its unnecessary, but...whatever. I feel this gives all my inhabitants a more natural life. Some things won't come out with the moons on, and I feel by varying it this way, it allows everything an equal chance to roam around the tank, comfortably, on it's own time.