Hanna Instruments HI 98202 - Manual

pNa
HI 98202
Soft Water Tester
GENERAL INFORMATION
The pNa tester utilizes a sodium ion-selective
electrode to determine the activity of free sodium
in solution (pNa = -log a
Na
).
In dilute solutions, the activity coefficient is nearly
1 and in such solutions pNa is a good indicator
of the sodium ion concentration. The relationship
between the pNa scale and the g/L Na
+ scale is
explained in the chart below.
A double junction reference is used to ensure a
highly stable reading. If you suspect that the
calibration has drifted, you can recalibrate the
meter by using a solution of known concentration.
Adjust the reading with the calibration trimmer.
HOW TO USE THE CHART
• Locate the pNa reading on the horizontal axis
of the chart.
• Move vertically upwards to intersect with the
45º line.
• Move horizontally and read the g/L Na value.
E.g. pNa = 1.4
g/L = 0.9
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