FWIW, I have shared your frustrations with determining water parameters using many hobby grade kits. I have been using the Salifert Test kits (except the pH kit) for a long time and am quite happy with the results. I also like buying my kits from
www.bulkreefsupply.com since I have always received fresh kits from them that have not set on shelves too long. The Salifert Test kit recalls (or problems) have not seemed to be any worse then other upper grade kits in this price range.
Another analogy: when I grab one of my wife's cheap screw drivers she proudly purchases at the grocery store for quite a reduced price and the blade of the screwdriver twists off the first time I try to use it. :lol: