Is this a sponge

[Missy blaze]

Hi all I'm starting a new Neptunian m180 and got a heap of cycled live rock from a fishless system and I have a lot of these while sponge or algee things showing up every where I tryed to google Id but still wasn't sure if anyone can help me
Thanks

 

[Timfish]

Looks like sponge to me but a closer picture would help. Cryptic sponges are ubiquitus to reef systems and essential recyclers of DOC. Like all the other biology in reef systems there will be cycles, especially when setting up a new ssytem. I wouldn't be surprised if in a year they are less noticable but may grow more the next weeks or months.

 

[Missy blaze]

I got some better photos it's growing mainly on the underside of rocks