In September 2012, we updated the Conductivity probe with a new calibration on each switch setting to optimize it for small improvements in the hardware.

Pre-Sept 2012 Calibration values:
Low Setting = 65.7 uS/cm
Middle Setting = 847.2 uS/cm
High Setting = 7819 uS/cm

Post-Sept 2012 Calibration values:
Low Setting = 65.7 uS/cm
Middle Setting = 960 uS/cm
High Setting = 9000 uS/cm

You may find that it improves the accuracy of your Pre-Sept 2012 Conductivity probe to burn onto the sensor the Post-Sept 2012 calibration values. To do this, see:
How do I store the calibration for my sensor using Logger Pro?.