First, we now know than ever that our corals are like the canary in the coal mine. They tell us a lot before any test can. But when it comes to testing. I'll give you an example my pH, I have three different devices. To make sure pH is accurate. I don't use any wet chemistry to test ph. I use electronic devices. So you may have to test different ways for each perimeter and see if you get the same results when it comes to alkalinity, nitrates etcYes I had/having same issue. So annoyed as I assumed the hanna checker for alk was one of the best testers and maybe it is but clearly I had a bad batch of reagent since results read 10.5 two days ago did a 10% water change tested next morning 11.5 was like "no way it's that high", opened a brand new reagent and test....7.9 salifert test confirms that as well. Another hard lesson learned. Guess I know why all my frogspawn died. $300 coral order every single one gone. So my question is what test/tester (other than of course the $1500 apex/trident) can be trusted?
Bummer