Live Rock Silk?

[fugzz]

Hey, i just bought an additional 3kilo's of liverock for my 2ft tank and growing on one particular piece is what looks to be a silver silky coating... Im not sure what it is, but it looks like a layer of silver silky algae or something? If any1 can identify this for me that would be good, and what i should do about it? and if it is harmful?

 

[ci11337]

I have some of that stuff too but not a clue as to what it is. my tank has been setup for over a year and I can't say it's caused any problems. I've always assumed it was some kinda sponge.

 

[krazekajin]

I believe that is a cynobacteria. It is caused by a high nutrient load and too little current.
I have had it in my 10g nano. The only way is to have a better filter and to have more current
It also could be that there was something that died on the liverock and the black silky stuff will go away once the dead matter has been consumed.