What's the light brown fluffy stuff

[kiwis]

I can brush most of it off but some of it is hard to get off parts of my rock. Any ideas?

 

[Webslinger]

sponge?

 

[Arthacker87]

I think possible sponge as well

 

[kiwis]

Okay, what's that? is it bad? how do you remove it and ultimately what caused it?

 

[Euphyllia97]

Sponge! It was probably introduced with some live rock and started growing until you noticed. I guess you can just scrape it. Sponges come of quite easily.

 

[Webslinger]

let it be

 

[Scape]

Yeah looks like a sponge, it can be removed but looks nice imo I agree let it be, Zoas look great btw.

 

[kiwis]

Yeah looks like a sponge, it can be removed but looks nice imo I agree let it be, Zoas look great btw.

There's a lot of it, any ideas how to remove it or is a matter of brushing it off by hand