For me, it's the cost that guides me. IO salts that way to go if money is a concern.
That said, I really don't have any experience with any other brand. I grow SPS predominant, but I do dose Calcium and Alkalinity, and Magnesium.
But I think that, when your corals start to grow significantly, you will need to dose to keep these parameters up anyway. So I'd rather do it this way than using expensive salt, and still having to dose, even if it is not dosing quite as much.
Hope this makes sense
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