Yeah, I know it is aggrevating and it would be nice of them to come clean, but you may be spending more $$ on this effort in terms of sending samples to them than if you had just bought another bag of salt.
Lesson learned here, for all, is if salt looks suspicious when you mix it, then definately don't use it. Salt is pretty darn cheap online so its not worth the risk of using it if your water stays cloudy as it did with you. There could be unknown variables involved. For instance the same exact cloudy water happened to me with 1 batch of using --. No matter how long I left it to mix, I still got cloudy water just like what you are showing in your tank. Now, you might conclude that the batch of salt was "bad". However, in my case, the batch of salt I made up before that was from the same container and was fine. The batch I made after the "cloudy moment" was fine too.
Go figure. What's the answer? Was the salt bad or did some sort of chemical thing happened out of the ordinary that caused this?? Only the chemist will know [maybe, or maybe not].
As hobbyists, the lesson is: if it looks suspious, then don't: use it, buy it, get it, put it in your tank. Thomas I'm not trying to lecture you, but, more just hoping that your exp with this that you are sharing will be a lesson learned for all of us. Better to waste a few bucks then our whole tank be wasted!