You are invited to my house to see for yourself.What I am saying Jason is this: In my opinion, in a freshly mixed batch of salt water that was made with good/clean RO/DI fresh water, you should not be able to test a detectable level of phosphates, nitrates and certainly NOT ammonia with hobbyist level reagent style test kits. I am also saying that you will not get detectable levels in any of the Tropic Marin salt mixes.
FWIW i run a prefilter, TWO carbon blocks, TWO RO membranes, and TWO di resin stages on my water mix. Tap is only 60tds to start with.
But..as i said, you are welcome to come to my house and check. Every major brand ive checked so far tests positive for nitrates.