I just got a um used but not used Pinpoint nitrate monitor from a friend. It was brand new in the box never used but judging from the box it has been sitting around for quite a while. I am trying to calibrate it and I keep getting a "High" message on the screen. Could the calibration fluid be out dated? I have it soaking in the 10ppm fluid right now, it says if troubles are encountered to soak it for 5 to 10 min.
I did the low calibration and when I test my water it just jumps all over the place?
Any suggestions?
I did the low calibration and when I test my water it just jumps all over the place?
Any suggestions?

