No, unlike the in line resistivity monitor/controller, the Myron L Ultrameter handheld instrument combines the unique ability to measure conductivity (0 to 200 mS) and resistivity (10 KΩ to 30 MΩ) ranges into one microprocessor based instrument. Since resistivity is the reciprocal of conductivity, the instrument only requires the calibration of a conductivity range using a Myron L standard. Once a liquid standard is used to properly calibrate a conductivity range, this will automatically ensure accurate measurements throughout the resistivity ranges.
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​Note: The resistivity ranges are calibrated only if the conductivity ranges are calibrated for the same solution. When using the Ultrameter to measure ultra pure water, a special technique is required to capture the water in the sensor well to reduce the affects of carbon dioxide in the sample. For detailed information on the calibration and the use of the EP, see the EP instruction manual. For detailed information on the calibration and use of the Ultrameter, see the Ultrameter operation manual.

Source: Myron L FAQ