I don't use salt mixes these days. Nice fringe benefit of running a wet lab is the use of NSW from a SW well
However, when I have used SW mixes of various brands over the years, they all would clump with exposure to moisture in the air. Wouldn't happen if they used anti caking agents like gettanked claims they all do
Besides, if it was really so necessary for mixing, how would he be able to mix salt without it himself? See what I'm driving at? Some claims are just marketing without real substance. Your more likely to find YSP used in water softener salts or table salt than sea salt mixes