I believe what the authet is presenting is what works for me might not for you. If i gave a sample of my water to 5 people and my test kits, maybe 1 or 2 will end up with similiar results. Also half would say i dont like these test kits.There are many different perceptions on how to read them. An example is every once in awhile ill take a sample to the lfs and have them run a test. Ive watched as one person fills a syringe to the top of the plunger and the next to the bottom. All because the instructions say fill to plunger.
Maybe the question should be what test kits are you currently using? I personally use salifert for alk, cal, mag, nitrate. And seachem for po4
Ph i dont really check, i figure if alk is stable ph is not really a concern. Although I do have a seachem kit for ph .