Please help indentify this grey stuff on Green Star??

[patrsnracn]

This appeared a few weeks ago, just a little spot. This guy is

growing and way happy, so have not noticed a problem. Well tonight after lights out this is what we found, and the original little spot is now looks like a knob, upper left
It's like ash and blows (but not completely) off using just a stream of water from turkey baster. It is also now on the substrate @ ~ 1 O'clock

What is it and what might we do about it?
Please Help, any info appreciated

 

[Diesel]

If it blows off it might be detritus settling and GSP doesn't like any of that.
Try to get more flow on it or move it up higher, only with a par of 200+ it might do good on the substrate.

 

[patrsnracn]

it blows of somewhat, but not like you would expect from detritus, acts like fungus in that it is spreading, it receives decent flow, waves around well. I can move it up

 

[Diesel]

In that case it might be a slime coat of some sort.
It's hard to tell from the pics.
Maybe a close up shot from the side.
Let me see if any of the [HASHTAG]#reefsquad[/HASHTAG] has seen this.

 

[reefwiser]

it could be a sponge. There are some sponges you see that are a grey color found on live rock.

 

[kireek]

I think your onto something Ed,maybe a cryptic sponge,?

 

[patrsnracn]

Again, it is very unconsolidated like ashes, I'm going to treat it today like bacteria in that the GSP its going to be cleaned in a Revive/Reef Dip combo for 15 min. and then rinsed well & returned home. I'll keep you posted