Hermit Crab shells turning white

[Nem0]

I've noticed that within the past few weeks many of my hermit crab's shells are turning white. Specifically near the end of the shell (the pointy part). Googling told me it might due to a lack of ALK or CA (i don't have a test kit, I'm running a FOWLR tank) but I use IO reef crystal salt which has a decent amount of both in the salt. Moreover, the ends seem to have become less pointy than when they initially started. Any ideas?

shell used to be the same color as the rest

 

[Reefer Reboot]

Over 24 hours and no one has answered? Okay, here's the scoop. Hermit crabs don't grow shells, they just "move in" to the empty ones. As they drag them around the shells wear down. That's why the pointy ends are turning white. As the hermit crabs grow they will need a selection of bigger shells to move into. Enjoy!

 

[Hermie]

one thing about hermit crabs is they are like hobos, they wear what they find, you can dress a hobo up in a tux but they will still be a hobo at heart

 

[Nem0]

okay great!!! good to know nothing is wrong :)