Water cloudy at night/clear during the day

[tangit!]

My daughter has a 155 reef tank. She also has moon lights for night vision. Every morning her tank is horribly dirty - the water. I mean particles of "stuff" floating around in it. But shortly after the day time lights come on, it clears up. I said it's her "critters" at night moving around and stirring things up.
Any other ideas/suggestions?
It DOES clear up, but then again the next morning it's horribly cloudy.
Thanks for any input.
We don't know what's going on...

 

[geoj]

What is different between the night and day?
Dose a filter become turned off at night?

 

[tangit!]

No. The only difference is the lights. The day time lights go off and she has "moon" lights that come on.

 

[oceana]

any sand sifters like a goby?

 

[tangit!]

She has a lawnmower blennie and a mandarin. Plus a couple starfish...bumblebee snails, hermit crabs, the usual crowd...

 

[lilzeus99]

Not sure, just an idea to talk about. Does she have anything in her reef tank like a clam or something that the lunar lights might stimulate a spawn?
Just thowing it out there for conversation.