Fine gray fuzz in my rocks

[Piratefish]

My rocks and some of the sand has this fine gray fuzz growing on it. The turbo snails don't seem to eat it. Its not slimy. Just fuzzy. Its not growing on the coraline just the bare rock.

Its not long its short maybe 1/4"

Any ideas? Water prams are all good ammonia 0 nitrite 0 nitrate 0 phos 0 Alk 9 Ca 420 mag 1250 Ph 8.1.

 

[Smitty]

I have no ideal...I have it on my rocks also, the ones in the back of the tank.

 

[yote]

I have no idea what thats called.But I've had it in my tank.Seems to go away as the tank matures.

 

[Piratefish]

Okay thanks.

It is mainly on the rocks in the back