White Stringy Substance?

[pkelly944]

This white hairy/stringy substance has been growing on my carbon media bag for a few months, the only place I have seen it growing in on the bag. The bag is with the skimmer in the sump.... any idea what it is an if its good or bad?

 

[neilanh]

Hmm, not sure what that is.

I updated the URL of your image though so it would show correctly here.

 

[ccCapt]

Looks like it might be some sort of sponge.
But my question is how is it even growing there? Carbon should be changed and that bag thoroughly cleaned at least once a month. Did that all grow in a months time?

 

[pkelly944]

Well it started growing and I was curious to what it was so I didn't change the carbon to not disturb it. It's been about 2 months growing, there is actually two patches of it on the bag, the other is just to the right of it in the picture on the bag