Is this some sort of sponge?

[b4tn]

I have these white branchy things growing all over the glass in my sump.

 

[Reefing Madness]

Bacteria. You can wipe it up.

 

[Ashish Patel]

Old thread but did you determine what this was? I have same things growing in my sump near the protein skimmer. Initially i thought it was detritus but it seems like stringy stuff is actually Sponge.. Not bacteria.

 

[Ashish Patel]

In case anyone else was searching for "white stringy stuff in sump"...I've identified mine as pineapple sponge..;)