What happened to my salt?

[Beverly]

I agree with humidity too. Had that happen to one of my pails. Now I close the lid tight (like I did before) and put something heavy on top of the salt pail to seal it even better. No more hard layer on top of the salt.

[midgetwaiter]

I had this happen with the last bit of an IO bucket recently. Looked like all the calcium was precipitating out and leaving a film on the inside of the bucket.

I just diluted it and used it in the brackish tank