I agree, its very easy to accurately read the API when you have a digital reading sitting next to you (or say the two appear to match exactly, definitely within the .25ppm range).
I would also like to think, I could test with the API now more accurately having the additional experience using the two in combination.
Prior to having the digital reading, I have found that my practice was reading the test wrong, having the mental piece that you need to make sure you are at least 2.0 with chelated copper, to error on the side of caution maintaining a therapeutic level.
Agreed. I just received my Hanna checker today and it tested 2.07ppm. My API color test led me to believe I was between 1.5-2, but closer to the 2. Like @HotRocks, I'm now a LOT more confident in my ability to read the API kit while I wait on my reinforcements from Hanna.
Thank you to all parties involved in getting this info to the rest of us.