I once sprung the extra $$ for a "premium" salt, the most expensive Red Coral was selling (before the current owner ran that store), which was Aquamedic. Boy was that ever a lesson. I spent twice as much on that as I could have on say IO, but the difference was that the "parameters" printed on the box were a complete fabrication. Magnesium at 1200! But gee, don't test it because it's really only 700 or so. I was blown away, why go to the trouble of printing numbers on the bucket if they don't in any way match reality? Similar story for Ca and Alk numbers. Complete fabrications.
My advice? Find a salt you like, stick with it, but test it before you use it so you know what you're putting in.
I'm continually behind the curve on this one. People seem to rant and rave about some salt brand, so I'll try it, but I'll finish off what I have before using it. Last year the flavour of the day was RBS, I finally finished off my last bucket of my last batch of salt this morning, and cracked open the RBS, so I'm about to see if I like it too. But then I read this thread and see the flavour of the day has moved onto a different brand.
To be honest, I never had an issue with IO. I didn't mind the lower Ca and Alk because I dosed that anyhow. Then I switched to Kent and had many trouble free years of use until the bad Alk batch. I sent in for a replacement bucket like so many others but I guess they didn't like me or something because they never sent me the replacement. So I'm not a fan of Kent anymore.
Should have just stuck with IO.
But I am excited to finally get to try RBS. Yay!