There are two possibilities.
All our instruments have the ability to have MINOR adjustments made to them by the user to remove these differences. Any major adjustments really do require a visit to our workshop to ensure that there isn’t something more fundamentaly wrong with the instrument. A minor adjustment would be up to the range of error tolerance for the individual instrument.
Purchase a known calibration standard from us (part No 1900-6352) and check your meter against them to determine which, if any, require recalibration, or in the case of GrainSpears, one of our Field Test Devices (part No 1900-6280).
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