AquaMetrix Aqua-Check, Operator'S Manual

Chapter 3

15

Operation

After the dissolved oxygen sensor calibration is complete, the Water Analyzer will
resume displaying the four measured parameters: temperature, pH, conductivity,
and oxygen.

pH Sensor Calibration

For maximum accuracy, the pH sensor is calibrated at three points:  acid point,
base point, and neutral point.

1. Turn on the Water Analyzer and let the readings stabilize.

2. Completely immerse the pH sensor in a pH 4 buffer.

3. Press the [MODE] key to reach the Mode menu. Press either the 

[UP] 

and

[DOWN] key until “Calibrate pH” is displayed. Press the [ENTER] key to
select the Calibrate pH Mode.

4. The top line of the display will now read “pH low cal 4.00”. The 

[UP] 

and

[DOWN] keys can be used to adjust this to a different value if desired.

5. The bottom line of the display will show an ADC value. When the displayed

ADC value stabilizes, press the [STORE] key to save the calibration informa-
tion. To skip this step, press the [ENTER] key and the previous information
will be used.

After the pH low cal point has been determined, the pH mid cal and the pH high
cal points will be prompted for. We recommend that pH 4, pH 7, and pH 10 buffers
be used for calibrating the pH sensor.

While the solutions used are buffers and will remain reasonably stable in pH value
in spite of slight dilution or contamination, the greatest accuracy will be obtained
by using fresh, clean buffers. After a solution has been used to calibrate a pH point,
discard it.

Once the pH high point has been determined, the meter will resume displaying the
measured values for the temperature, conductivity, pH, and oxygen.

Conductivity Sensor Calibration

The conductivity meter contained within the Water Analyzer has four ranges of
sensitivity. The Water Analyzer automatically selects the appropriate range for
displaying the conductivity value. Each range must be calibrated separately. We
recommend that all four ranges be calibrated at the same time rather than the single
range you may be using.

1. Turn on the Water Analyzer and press the [MODE] key to access the Mode

menu.

2. Press either the 

[UP] 

and [DOWN] key until the “Calibrate Cond” prompt is

displayed. Press the [ENTER] key to select the Calibration Cond Mode.