Yeah, I have this whole idea that it's offensive to buy the Merck/D-D test kit (it's not cheap) after spending the big money on the meter to begin with, but the lack of consistency in my results is something that really troubles/puzzles me. Have you tried taking 3 tests in a row with yours? When I do this I get three different numbers. I've finally figured out that at least one of my cuvets is suspect - if I zero out the meter, then immediately take a reading - I get an "underrange" error. (Consistently.. I tried it about 20 times.) I would expect it to be zero, or at the very least, "not always" underrange. With the other cuvet I can zero it, and get a zero reading. I wonder if the sensor or the LED emitter might have dust on it too but it would be impossible to clean those I think so I kind of hope that's not the case.
Yikes, 500ppm seems for sure too high, I would have backed off the reactors as well! Might need to be upped just ever-so-slightly now just to find the happy medium..
Wow, 65lbs of rock, that's a lot more than I thought there was in there.
