Please help ID

[ymh1253]

I wish I had a better pic of this thing, but it's white, roughly a half inch long, and branches. I noticed it growing on the side of some live rock today. Any idea's as to what it might be? Calcium build-up maybe?. Thx

[salvini55]

it is too difficult to tell with that photo, whish I could help more

[BOnaqua]

I believe it's a white sponge.
Very comon in tanks.
Almost always grows on the side of rocks.