HELP!!! What kind of salt can i use for my Fiddler Crabs??

I just purchased my fiddler crabs and i found out after doing some research that they need salt, unfortunatley i dont have any aquarium salt and i live in a small town and the nearest place i could get some is about an hour or so away. I read somewhere you could use Kosher or canning salt, and i think that can be picked up in just about any grocery store. So my question first of all is two fold, first of all,


Can i use Kosher or Canning Salt for my crabs?

then


Can i find this kind of salt at any grocery store?

hmmmm i wouldn't do that. i would just drive and stock up on salt water aquarium salt or order it online

I read that you can, but you don't want to use salt that includes potassium or iodine. I also read that sea salt could work. Just make sure there are NO ADDITIVES.