Can anyone ID this?

[dustyboy316]

This just popped up on one of my rocks last night. It's just some white stuff, but I have nooo clue what it can be?
It's on the left rock. Thanks.

 

[spanko]

Is it powdery, can be blown off? Maybe some precipitate.
Is it hard? Maybe bleached out coralline.

 

[nissan577]

can you circle it or something? it will help

 

[dustyboy316]

yup one sec. I'll check to see if it is easy to scrape off too.
Looked like on e of my emeralds was going after it.

Edit: It dosen't come off the rock easily. It was kinda slimy. Could it be the start of some corraline?
It looks like I'm growing some coralline or a sponge in another part of the tank too?

 

[dustyboy316]

Anything?

 

[dustyboy316]

*Tumble Weed*

 

[grubsnaek]

its either sand, or coralline algea bleaching

 

[dustyboy316]

ok must be some coralline bleaching. It isn't sand.
Thanks.