LaMotte Tracer pH Meter - Manual (Page 8)

8
RENEW
A fl ashing “RENEW” warning indicates that the probe may be nearing the end
of its useful life. If cleaning or recalibration does not cause the
Renew
icon to
disappear, replace the electrode (see optional accessories). The
Renew
display
appears when the output of the pH electrode fails a diagnostic test.
pH TESTING
Overview
pH is a unit of measure (ranging from 0 to 14 pH) indicating the degree of
acidity or alkalinity of a solution. pH tests are the most commonly performed
measurements in water analysis, using the negative log of the hydrogen ion
activity of a solution which is an indicator of acidity or alkalinity. Solutions
with a pH of less than 7 are considered acidic, solutions with a pH of higher
than 7 are known as bases, and solutions with a pH of exactly 7 are considered
neutral.
The pH scale is logarithmic, so, for example, if Sample A is 1 pH less than
Sample B, this means that sample A is 10 times more acidic than Sample B.
A difference of 1 pH represents a ten-fold increase or decrease in acidity.
pH Display
When the electrode is placed in a solution, the main display and bar graph
will indicate the pH reading while the lower display will read temperature.
Readings fl ash until they have stabilized. The bar graph is ‘center zero’, i.e. at
pH 7 there is no display. As the pH rises, the bar will move from the center to
the right. If the pH drops, the bar will move from the center to the left.
Getting Started
1. Remove the cap from the bottom of the TRACER to expose the electrode
glass surface and reference junction.
2. Before fi rst use or after storage, soak the electrode (with cap removed) in
a pH 4 buffer or tap water for 10 minutes.
3. Before fi rst use, hold the meter by the top battery compartment and
swiftly tap the back of the meter downward into your palm (not a hard
surface). This assures that the internal electrolyte solution moves to the
very tip of the electrode. The electrolyte should fi ll the circular junction
window at the tip of the electrode.
4. White KCl crystals may be present in the cap. These crystals will dissolve
in the soak or they can be rinsed off with tap water.
5. Always calibrate close to the expected measurement value.