Cloudy water - please ID

#1
this morning before I left to go to class, I noticed my water was very cloudy; It looked like a freshwater bacterial bloom. The strange thing is, when I turned the lights on, there was only a slight haziness to the water; 20 minutes later, it was very cloudy. Now that I've returned from the class - less than 2 hrs later - the water is starting to clear.

I was thinking something must have gone sexual, but there isn't much in there to do so... no macro algae, corals or anything else that is known for it.

The only living things I know about are 2 asterina stars, a small mullosc(clam or mussell that was on the live rock, I'm 60% sure it is living), one fan worm, pods, bristle/spaghetti/peanut worms, and a ton of hair algae.

The tank hasn't completely cycled, but is nearly there; ammonia is at 0, NO2 is 0.3ppm and NO3 is 50ppm.

What could cause it to cloud, and clear, so quickly?