White Sponge Taking Over!

I have some stuff growing on my rocks I can only describe as a white sponge. It grows ridiculously fast and has even spred to some base non live rocks I have in the tank.

Should I be worried?

 

I have something like that I just picked out of some cheato that I have. I'd like to know more too.

 

sponges are good.
Xtalreef

 

Not all sponge is good, if it's white-pinkish and growing on top of the rock get rid of it.

 

Do they look like this

Melevsreef.com - Scypha Sponge

 

no not at all. it is like a big enveloping mass sort of like a bunh of wet tissues stack on each other

 

I've got a ton of those in my tank, all over my rock, and in my Bak-Pak water column.

This looks like the same thing I had in my 150G before my porcupine ate it. I was told it was a tunicate and is harmless. I thought it was a fungal mass at first.