Something strange here...

[ger87410]

How on earth does crabs get calcium from sodium chloride (salt)? It's the wrong chemical. Shouldn't a cuddlebone make up for any calcium they might want? U just can't get calcium from salt.

 

[Teelie]

Yeah, doesn't make sense they'd get calcium from salt though they do need salt, they need the calcium too.

 

[orientboy]

Maybe it isnt just NaCl in salt but other compounds as well, maybe the crab needs the salt to facilite the uptake of calcium

or maybe they mean salt in a chemical sence rather than commen table salt (NaCl)

 

[ger87410]

There is no salt that contains calcium. Except calcium chloride (hardly anybody uses this). I'm not even sure that's salt. If crabs need the salt it's gotta be for a different reason other then for calcium. Calcium is in hard water. So shouldn't the water just be hard?

 

[Teelie]

Well the most obvious reason is most crabs are either saltwater or brackish and the few freshwater crabs always seem to benefit from some salt in their water, probably the same reason most fish benefit from it as well. It helps in gill regulation, water retention (to a point) and several other biological functions.

 

[ger87410]

I think the point that I'm trying to make is not quite coming across or is being sidestepped. What is the hardness of the water that these things come from? Is it soft or hard? Isn't sea water and most natural brackish water hard? If it's that the crabs need calcium, then shouldn't they be in hard brackish water as opposed to soft water? So logical, the crabs need hard water more then they need the salt in it. If they are the only crab and they can easily get to numerous hard to reach hiding spots not to mention the only one that can leave the tank then the shell hardening quickly won't matter except disease right. Shouldn't them being able to get out of the tank facilitate shell hardening?