White crust on turbo snail

[learn2reef]

What is this white crust on my Mexican turbo snails? I got them from the LFS and most have it. Toothbrush doesn’t get it off. I can flake off some bits with my fingernail. Most i can’t though. I did just add some CA to raise the level in the quarantine tank. Could it be calcium deposits? I do feel like there is more of it now than a few days ago.

Thanks!

 

[shwareefer]

Coraline algae.

 

[Isopod80]

Calcium deposits from dead corraline or other calcified former organisms. Some look like areas where the outer shell has been worn down a bit. Nothing to worry about.