Hello everyone! Not too kick a dead horse again but here it goes. I am having same issue. Using a pinpoint pH monitor and apex pH. A few weeks ago I had both monitors calibrated exactly! I have never achieved this before, it was so cool! But pH drift affect one or the other and now I am re-calibrating, or at least trying.
I have read all the threads...and followed directions.... plus I have a PhD in biomedical sciences and have years of lab experience, so this is very frustrating!
The first thing I noticed was in the local screen for pH control the offset and scale were way off, didn't write those down. I performed the reset process getting the offset back to -92 and scale to 1.114, these are the values Neptune says are standard.
Ran manual calibration pH 7.00 solution at 6.99 and pH 10.00 at 9.99, very happy with that, I moved them back and forth with consistent readings.
Clicked update settings and the offset changed to -31 and scale to 1.09b (yes b) all I can think of is slope equation of y=mx+b but I have no real idea.
Placed probes back in respective solutions and got 6.99 and 9.99 ; pinpoint 7.00 and 9.99
Placed probes in tank... 8.01 for pinpoint and 7.90 for Apex. Assuming the pinpoint is closer to correct, its the middle of the day and lights are running full blast, so would actually expect levels to be closer to 8.2 to 8.3
Any ideas, I remember something from analytical chemistry about concave and convex calibration curve errors and I can see that my apex curve is dropping between too calibration points, this should have gone away after resetting....
I have read all the threads...and followed directions.... plus I have a PhD in biomedical sciences and have years of lab experience, so this is very frustrating!
The first thing I noticed was in the local screen for pH control the offset and scale were way off, didn't write those down. I performed the reset process getting the offset back to -92 and scale to 1.114, these are the values Neptune says are standard.
Ran manual calibration pH 7.00 solution at 6.99 and pH 10.00 at 9.99, very happy with that, I moved them back and forth with consistent readings.
Clicked update settings and the offset changed to -31 and scale to 1.09b (yes b) all I can think of is slope equation of y=mx+b but I have no real idea.
Placed probes back in respective solutions and got 6.99 and 9.99 ; pinpoint 7.00 and 9.99
Placed probes in tank... 8.01 for pinpoint and 7.90 for Apex. Assuming the pinpoint is closer to correct, its the middle of the day and lights are running full blast, so would actually expect levels to be closer to 8.2 to 8.3
Any ideas, I remember something from analytical chemistry about concave and convex calibration curve errors and I can see that my apex curve is dropping between too calibration points, this should have gone away after resetting....
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