What is this lint stuff on live rock? (Pics included)

[first29gallon]

I just noticed this white lint/thread stuff all over the live rock in my tank? Does any know what it is and whether I should be concerned? I've had the tank up and running for 2 months and used live rock.

 

[Sk8r]

Could be bacterial. I've seen it, but not that extensive, and it could be rock dust coating algae, making it more visible. I've not known it to be troublesome, but will be interested to hear other experience.

 

[first29gallon]

Anyone?

 

[ethuman]

I had a small spot with this type of "stuff" on it but it was only about the size of a dollar. Couldn't find much about it but it didn't seem to get any bigger/worse after I let it sit for a couple days and about a week later it was just gone. Still to this day I have no idea what it was but also didn't have anything else harmed in the tank so I wasn't overly concerned

 

[first29gallon]

Now it's getting worse but all my fish\inverts are acting fine. This stuff looks so ugly. Please help. I want to take the rocks out and scrub them tomorrow but I have a feeling it will come back.