I did siphon that area and it seems to slowly be coming back in the same area. Diatoms maybe? I don't think it's dinos either like you described mojuave. My clean up crew definitely needs replenished, but I haven't made it to the LFS that has them 20 for 10 because it's a 45 min drive. Petco is the only thing really close to me and I really don't like to buy there just because I have noticed cyano in their tanks plus I can't see spending 2 something on one crab or snail. I have only been running my day bulbs 3 hours lately because I know they need replaced. I run blue 10 hours and my corals are loving it since those bulbs are new. I also hooked back up my algae scrubber. Not sure if it will help, but worth a try. When I ran it before it was only for like a month so I never really gave it long enough to see if it would have the results it is supposed to. My nitrates still run 10-20 no matter what I have did so far. Considering trying to build a sump/fuge, but still researching that. Whatever this is I'm sure it too will pass, at least I hope.