Hach POCKET COLORIMETER II Instruction Manual page 28

Chlorine, Free and Total, LR,
continued
A user calibration or a user-prepared chlorine standard may be required by a
regulatory official or agency. Two options are available on the
Pocket Colorimeter II to meet this requirement.
A chlorine standard may be prepared and used to validate the calibration curve
using the Standard Calibration Adjust feature (see page 2—13 for more
information). The concentration of the prepared standard must be determined with
an alternate instrument such as a spectrophotometer, colorimeter, or by using an
alternate method such as amperometric titration. The concentration of the chlorine
standard for the LR procedure must be between 0.50 and 1.50 mg/L chlorine.
In addition, a user-generated calibration curve can be programmed into the
Pocket Colorimeter™ II. See User-Entered Calibration on page 2—15 for more
information.
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