Hach DR/850 Procedures Manual page 50

CHEMICAL ANALYSIS INFORMATION
Figure 11 Logarithmic Calibration Curve
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To convert %T readings to concentration, prepare a table such as Table 7
and select the appropriate line from the "%T Tens" column and the
appropriate column from the %T Units columns. The %T Ten value is the
first number of the %T reading and the %T Units value is the second
number of the %T reading. For example, if the instrument reading was
46%, the 40 line in the %T Tens column and the 6 column in the %T
Units would be selected. The cell where these two intersect (0.78 mg/L) is
the iron concentration of the sample.
, continued
mg/L IRON
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