Your FAQ says this:

Changing the Calibration Factor for Hanna Meters (HI98311 and HI98129)
Press MODE button, the Beta factor will appear. DO NOT CHANGE THIS, it should remain at 1.9.
Your Hanna meter is now ready to be calibrated using the Genesis calibration solutions.

But, when I use that Beta factor, my readings seem to be too high. Are you sure this isn't a misprint? When I use a Beta factor of 2.1, then my calibration seems to be successful and I get the readings I expect (on the Genesis 1413 us/989ppm solution).