can't keep crabs alive?

[166north]

ok, here is my question. i've had my tank up for a few years now. most things seem to do ok, i mean, well, my corals don't really grow but they aren't dieing anymore either. anyways. for some reason, anytime i throw in hermit crabs or anything like that. they never seem to live. my snails are all happy and fine. doesn't seem like the shells are crushed so nothing is eating them. any thoughts?

 

[Letmegrow]

Make sure you Salinity is 1.025 checked on a refractometer and your temp is a steady 82F.

That is the most common and likely cause.