Trochus Snail Broken/Cracked Shell

[wrassyreefer]

Will this regrow and heal? I don't think he is exposed in anyway. When I got it home from the LFS there was a round piece of his shell that had come off. I have an extra shell but not sure if they switch or if it grows with them.

Thanks!

Sorry for the bad pics:

 

[Dapperjman]

Wow, I'd like to know this too. Bump!

 

[K. Steven]

Snails secrete their own shell out of calcium carbonate, so maintaining sufficient calcium and alkalinity should allow them to repair the shell.