FWIW-
I tried 3 different test kits, Seachem, quick-dip strips, and now the hagen master kit.
The hagen is by far the easiest and accurate, IMO.
I got it from ebay, $50.00 or so, came in a hard carrying case with:
NO2, NO3, AMM, PO4, Iron, PH, CA, kH.
It works great, even has a set-up inside...