Bug in Calibrating PH

[xiaan]

I just installed a new PH probe on my system and I had an issue calibrating it. when setting up what calibration solutions to use it kept telling me that 7.00 was to close to the other setting. I realized that the last calibration settings were set to 4 & 7 and I was trying to set them up to 7 & 9 when I was setting the low value to 7 the controller was rejecting the value because it thought was gong to set 7 & 7 as my calibration values. the workaround was to do a fake calibration of 4 & 9 then do the actual calibration of 7 & 9.

[Matthias]

I tested this:
1. calibration with 4 and 7
2. calibration with 7 and 9

what am I missing here?

[xiaan]

I tested this:
1. calibration with 4 and 7
2. calibration with 7 and 9

what am I missing here?

I do not know. All I know is that when my system was initial calibrated with 4 and 7 and when I switched to 7 & 9 my controller told me that the minimum calibration value was too high (or something).