Water Salts

My local brew store sells 'water salts' - a combination of magnesium sulfate and calcium sulphate.
I've nver heard of these two.
Anyone out there who has and would like to share?

I wouldn't use those unless it states what percentage the two salts are in the whole, and they meet your needs in that ratio.

My earnest suggestion is to read the water treatment section of howtobrew.com to see why you would want to treat your water and what you might buy by treating it. There are pros and cons to it, and you will need to start with knowing an analysis for your brewing water as it is (without any salts added).