funny, you like IO, I started using CL in the early 90's both those salt's get bad raps in a lot of forums and I have actually been convinced to use some other salts, none of which I am happy with, I am going back to CL and I do like IO but now I have quit a bit of various salt just stacked up in my garage.
someone asked "what is the test of a good salt?"
to that I would say: how do your corals look?
try not to loose sight of the objective which for me, is not trying to get the exact values on the FEW parameters of seawater that we test for. For me the objective is to raise big healthy beautiful corrals. the dozen or so parameters that we test for are guide to help us out if we are headed for trouble, or if we are in trouble to figure out what it is. experience and observations can often tell you more than the most exhaustive testing available to us