Hach H125 Operating Instructions
Continue as follows for two-point calibration
TIP: When using two-point calibration, always bracket the expected pH value of the sample.
For example, if the expected pH of a sample is pH 5.0, use pH 7.00 and pH 4.01 buffer.
8. Apply one drop of either pH 4.01 or pH 10.01 buffer to the probe tip.
9. Depress the CAL 2 button with the tip of the clip. The meter will automatically identify the
buffer value.
10. The CAL icon will flash until a stable reading is obtained. When the CAL disappears,
calibration of the second point is complete.
11. Rinse the probe in tap water and blot dry. To measure the pH of a sample, go to Step 12.
To continue with a three point calibration, go to Step 13.
12. Now measure the sample pH by placing a single drop on the probe tip or dipping the probe tip
into solution.
Continue as follows for three point calibration
TIP: Use three-point calibration when the expected sample pH values are completely unknown or
range both above and below pH 7.0.
13. Apply one drop of the remaining buffer (either pH 4.01 or pH 10.01) to the probe tip.
14. Depress the CAL 2 button with the tip of the clip. The meter will automatically identify the
buffer value.
15. The CAL icon will flash until a stable reading is obtained. When the CAL disappears, calibration
of the third point is complete.
16. Rinse the probe in tap water and blot dry.
17. Now measure the sample pH by placing a single drop on the probe tip or dipping the probe tip
into solution.
Model H125
pH Meter with Silicon Chip Sensor
IQ Scientific Instruments
Calibration and Measurement Instructions
Parts
When finished, always rinse the probe and replace the protective cap.
C
Remove cap from probe
tip and turn on the meter.
Rinse the probe in tap
water and blot dry.
Apply one drop of 7.00
buffer to the probe tip. Be
sure to cover both the
reference junction and the
pH sensor.
Depress the CAL 1 button
with the tip of the clip.
The CAL and 7.0 will flash
until a stable reading is
obtained. When the CAL
disappears and 7.0 stops
blinking, calibration is
complete.
Rinse the probe in tap
water and blot dry.
To measure the pH of a
sample, go to Step 7.
To continue with a two
point calibration, go to
Step 8.
Now measure the sample
pH by placing a single
drop on the probe tip or
dipping the probe tip
into solution.
1
2
3
4
5
6
7
6. Protective Cap
7. Clip
8. Bubble
9. POWER Button
10. CAL 1 Button
1.
Probe Tip
pH sensor and reference electrode.
2.
pH Sensor
Fast response silicon chip pH sensor with built-in temperature sensor.
3.
Reference Electrode
Replaceable saturated KCl Ag/AgCl electrode.
4.
Reference Junction
Measurement is made when the reference junction and the pH sensor are
immersed in the solution.
5.
LCD Display
CAL (blinking): Calibration in process. Measurement cannot be made.
CAL (off): Measurement can be made.
BAT: Low battery indicator. Replace batteries.
6.
Protective Cap
Always replace the cap after use.
7.
Clip
Use the tip of the clip to depress the CAL button.
8.
Bubble
The reference solution bubble indicates the life of the reference electrode.
9.
POWER Button
Press to turn the meter on or off.
10.
CAL 1 Button
Button for pH 7.0 calibration.
11. CAL 2 Button
Button for pH 4.0 or pH 10.0 calibration.
11. CAL 2 Button
1. Probe Tip
2. pH Sensor
3. Reference Electrode
4. Reference Junction
5. LCD Display
OPERATING INSTRUCTIONS
pH Sensor
Reference Junction
5600 Lindbergh Dr., Loveland, CO 80539
T
Te
ecch
hn
niicca
all S
Su
up
pp
po
orrtt::
(800) 227-4224 (U.S.A. only)
Fax (970) 669-2932
orders@hach.com • www.hach.com
International customers:
Tel +001 (970) 669-3050
Fax +001 (970) 669-2932
intl@hach.com
DOC022.53.80060
mini_man_H125 9/8/09 9:28 AM Page 1