Probably not a critter but what is this?

[miltonkl]

So I recentlly tried switching to Red Sea pro and it mixed incredibly, incredibly dirty. Brown residue all over my brute can and filled my display, I finally got around to cleaning out Most or the brown crap by now the back chambers of my AIO are filled with this stuff. Is this… anything? Maybe a sponge or something? I had a piece of marine pure in my display leaned against the back wall that also had it all over just the underside that wasn’t exposed to the tank lights.

i assume it’s not related to the salt but the residue masked it until I was able to clean that up.

 

[bradleym]

It looks like a huge collection of pineapple sponges.