Is this a type of sponge? ID

[PotteryMan]

Saw this today. It is growing out of live rock, white, and has branches. is it a type of sponge????

 

[cloak]

It's kind of hard to tell. It might be a sponge, it could also be some type of macro algae. Dictyota perhaps?

 

[PotteryMan]

I had to take the pic with my phone. DSLR is at work. It looks a lot larger in the pic than it is. It is roughly 2 inches across.

edit: also I am having an algae outbreak. just installed GFO reactor today. Tank has been up for about 9 weeks.