I heard you cannot over salt hermit crab salt water. They said the saltier the better, is this true?

you should be using instant ocean or a comparable marine salt ... and it should have a specific gravity of 1.020-1.027 ... too strong is no good and too little is no good ... and don't use any hermit crab water conditioners or salt soaks, it has to be fish water dechlorinator and marine salt ...