Hanna Instruments HI 99121 User manual

INSTRUCTION MANUAL
HI99121
Direct Soil pH Portable Meter

Thank you for choosing a Hanna Instruments product.
Please read this instruction manual carefully before using the instrument.
This manual will provide you with the necessary information for correct use of
the instrument, as well as a precise idea of its versatility.
If you need additional technical information, do not hesitate to e‑mail us at
[email protected] or view our worldwide contact list at www.hannainst.com.
All rights are reserved. Reproduction in whole or in part is prohibited without the written consent of the
copyright owner, Hanna Instruments Inc., Woonsocket, Rhode Island, 02895, USA.
Dear
Customer,

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Table of Contents................................................................................................................
Preliminary Examination .....................................................................................................
General Description and Intended Use..................................................................................
Main Features....................................................................................................................
Specifications.....................................................................................................................
Display Description.............................................................................................................
Operational Guide ..............................................................................................................
Meter Setup.......................................................................................................................
Soil pH..............................................................................................................................
Organic Substrate...............................................................................................................
Irrigation Water..................................................................................................................
Nutrient Solution................................................................................................................
Battery Replacement...........................................................................................................
Electrode Maintenance........................................................................................................
Accessories.........................................................................................................................
Certification........................................................................................................................
Recommendation for Users..................................................................................................
Warranty ...........................................................................................................................
TABLE OF CONTENTS
4
4
6
7
12
5
6
16
11
16
3
17
19
20
21
22
23
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4
PRELIMINARY EXAMINATION
GENERAL DESCRIPTION and INTENDED USE
Remove the meter from the packing material and examine it carefully to make sure that no
damage has occurred during shipment. If noticeable damage is evident, contact your local Hanna
Instruments Office.
Each meter is supplied complete with:
• HI12923 pH/temperature probe
• pH 4.01 & 7.01 Buffer sachet
• HI700663 electrode cleaning solution for soil deposits (1 sachet)
• HI700664 electrode cleaning solution for humus deposits (1 sachet)
• HI7051M soil preparation solution
• HI721319 ground auger
• 100 mL beaker (1 pc.)
• Alkaline batteries: 1.5V AAA (3 pcs.)
• Rugged carrying case
• Calibration certificate of meter
• Calibration certificate of probe
• Instruction manual
Note: Save all packing material until you are sure that the meter functions correctly. All
defective items must be returned in the original packing together with the supplied accessories.
The HI99121 is the perfect portable pH meter for soil testing. With the HI99121 and HI12923
direct soil pre‑amplified pH and temperature probe, users can test both the pH of soil directly or after
preparation of a soil slurry with deionized water.
The HI12923 features a conical, rugged tip that can be directly used in soil. A plastic auger is sup‑
plied to perforate and loosen the soil prior to sensor measurement. Use this tool to prevent scratching
the pH sensitive glass on nutrient crystals or small pebbles.

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MAIN FEATURES
Main features:
• Simultaneous pH and temperature measurements on a large dual‑line LCD display
• Automatic pH calibration at one or two points within two memorized buffer sets (standard or
NIST)
• Selectable temperature unit (°C or °F)
• Electrode condition indicator
• mV of pH measurement for electrode check
• HI12923 dedicated pH with integral temperature sensor
• Probe quick connect system
• Battery life indication and low battery detection
• Keystroke confirmation tone
• Auto‑off function
• Waterproof casing IP67

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Range*
‑2.00 to 16.00 pH / ‑2.0 to 16.0 pH
±825 mV (pH‑mV)
‑5.0 to 105.0 °C/23.0 to 221.0 °F
Resolution
0.01 pH / 0.1 pH
1 mV
0.1 °C/0.1 °F
Accuracy
@ 20 °C / 68 °F
±0.02 pH / ±0.1 pH
±1 mV (pH‑mV)
±0.5 °C up to 60 °C; ±1.0 °C outside
±1.0 °F up to 140 °F; ±2.0 °F outside
Temperature
compensation
Automatic
‑5.0 to 105.0 °C/23.0 to 221.0 °F
pH Calibration Automatic, 1 or 2 point selectable buffer set Standard: 4.01;7.01;10.01 or
NIST: 4.01;6.86;9.18
Probe (included) HI12923 glass body, pre‑amplified pH electrode for soil measurement with internal
temperature sensor, DIN connector and 1 m (3.3’) cable (included)
Battery type / life 1.5V AAA (3 pcs.)
approx. 1400 hours of continuous use
Auto‑Off user selectable: after 8 min, 60 min or disabled
Environment 0 to 50 °C (32 to 122 °F)
RH max. 100%
Meter Dimensions 154 x 63 x 30 mm (6.1 x 2.5 x 1.2”)
Meter Mass
(with batteries) 196 g (6.91 oz.)
Case Ingress Protection
Rating
IP67
SPECIFICATIONS
* the HI12923 is limited to be used from 0‑12 pH and from ‑5 to 70 °C temperature (23 to 158 °F).
DISPLAY DESCRIPTION
1 Automatic Temperature Compensation
indicator
2 Stability indicator
3 Battery percentage
4 Electrode condition indicator
5 Low battery indicator
6 Measurement unit
7 Primary LCD

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OPERATIONAL GUIDE
Each meter is supplied with batteries. Before using the meter for the first time, open the battery
compartment and insert batteries, observing the polarity (see “Battery Replacement“).
TO CONNECT THE ELECTRODE
With the meter turned off, connect the HI12923 probe to the DIN socket on the bottom of the meter
by aligning the pins and pushing in the plug firmly. Remove the protective cap from the probe before
taking any measurements.
TO TURN THE METER ON
To turn the meter ON, press the button on the front of the meter. If it does not turn on, make sure
that the batteries are properly installed in their place. The meter is provided with an active acoustic
tone that confirms when a key is pressed. At start‑up the meter displays all LCD segments for a
few seconds, followed by the percentage indication of the remaining battery life, displays “WAIT”
while doing an electrode check and then enters the normal measurement mode.
Note: The meter detects the presence and the type of the probe at its input.
- If the probe is not connected the message “NO” ”PROBE“ appears on the secondary LCD with
“---“ blinking on the first LCD line.
- If the probe is not compatible “WRONG” ”PROBE“ message appears on the secondary LCD
with “---“ blinking on the first LCD line.
- If the readings are out of range, the nearest range limits are displayed blinking (E.g. -2.00 pH
-5.0 °C).
TO SELECT THE MEASUREMENT RANGE
While in measurement mode, press the SET button to select pH or pH‑mV measurement on the first
LCD line.
Measurement
mode
Battery life
LCD
check up
→ →
→
Electrode
check
8 Temperature unit 9 Secondary LCD
10 Meter modes indicator 11 pH calibration buffer(s) used

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OPERATIONAL GUIDE
pH MEASUREMENT & CALIBRATION
Make sure the meter has been calibrated before use. If the probe is dry, soak it in HI70300 storage
solution for 30 minutes to reactivate it. If fouled, clean the electrode before use. Soak the electrode
tip in cleaning solution for 20 minutes, then rinse in clean water and soak for 30 minutes in electrode
storage solution to rehydrate it. Recalibrate before using. Submerge the probe in the sample to be
tested while stirring it gently. Wait until the tag on the LCD disappears.
The LCD displays the pH value (automatically compensated for temperature) on
the primary LCD, while the secondary LCD displays the sample temperature.
If measurements are taken in different samples successively, rinse the probe tip
thoroughly†to eliminate cross‑contamination. After cleaning, rinse the probe tip
with some deionized water and some of the sample to be measured.
For better accuracy, frequent calibration of the pH sensor with the meter is recommended. In
addition, the meter must be recalibrated whenever:
a) The pH electrode is replaced.
b) After testing aggressive chemicals.
c) Where high accuracy is required.
d) At least once a month.
e) After cleaning the sensor.
†The probe tip should be rinsed with purified water (reverse osmosis, distilled, or deionized) before and after placing in any solution
(buffer, storage, or sample).
→
TO FREEZE THE MEASUREMENT VALUES
While in measurement mode, press and hold the SET button until “HOLD“ appears on the second‑
ary LCD. The “HOLD“ remains for 1 second and reading of pH, mV and temperature will be
frozen on the LCD with “H” blinking.
Press any button to resume active measurements.
TO ENTER CALIBRATION MODE
Press and hold the button until ”POWER” and tag is replaced by “STD“ and tag.
Release the button.
TO ENTER SETUP MODE
Press and hold button until “STD“ and tag is replaced by “SETUP“ and tag.
Release the button.
TO TURN THE METER OFF
While in measurement mode, press the button.”POWER” and tag will appear. Release
the button.

9
OPERATIONAL GUIDE
pH calibration
Enter calibration mode while in pH measurement mode. Place the sensor into the
first calibration buffer. If performing a two‑point calibration, use pH 7.01 (pH
6.86 for NIST) buffer first. The meter will enter the calibration mode, display‑
ing “pH 7.01 USE” and tag blinking (or “pH 6.86 USE” for NIST).
Follow directions for single and two‑point calibration below:
Single-point calibration
1. Place the probe in any buffer from the selected buffer set. The meter will automatically recognize
the buffer value.
2. If the buffer is not recognized or the calibration offset is out of the accepted range “---- WRONG“
is displayed.
3. If the buffer is recognized “REC“ is displayed then “WAIT“ until the calibration is accepted.
If using pH 7.01 (or pH 6.86 for NIST), after acceptance of the buffer press any key to exit. The
”SAVE” message is displayed and the meter returns to pH measurement mode.
If using pH 4.01 or 10.01 (or pH 9.18 for NIST) buffer the ”SAVE” message is displayed and
meter returns to pH measurement mode.
Two-point calibration
Proceed with steps 1 through 3 under single point calibration using 7.01 (pH 6.86 for NIST) pH
buffer first. Then follow steps below:
The ”pH 4.01 USE” message is then displayed.
Place the probe in the second calibration buffer (pH 4.01 or 10.01, or, if using NIST, pH 4.01
or 9.18). When the second buffer is accepted, the LCD will display “SAVE” for 1 second and the
meter will return to the normal measurement mode.
If the buffer is not recognized or the slope is out of accepted range ”--- WRONG” is displayed.
Change the buffer, clean the electrode or press any key to exit calibration.
It is always recommended to carry out a two‑point calibration for better accuracy.
When the calibration procedure is completed, the tag is turned on together with the calibrated
points.
To exit calibration and reset default values
After entering the calibration mode and before the first point is accepted, it is possible to quit the
procedure and return to the last calibration data by pressing the button. The LCD displays “ESC“
for 1 second and the meter returns to normal mode.
To reset the default values and clear a previous calibration, press the SET button after entering the
calibration mode and before the first point is accepted.
The LCD displays “CLEAR“ for 1 second, the meter resets to the default calibration and the
tag with the calibrated points on the LCD disappears.

10
OPERATIONAL GUIDE
ELECTRODE CONDITION
The display is provided with a probe icon (unless the feature is disabled from setup) which indicates
the electrode status after calibration. The “condition” remains active for 12 hours (unless the
batteries are removed).
The electrode condition is evaluated only if the current calibration has two points.
5 bars: excellent condition
4 bars: very good condition
3 bars: good condition
2 bars: fair condition
1 bar: poor condition
1 bar blinking: very poor condition
With 1 bar it is recommended to clean the electrode and recalibrate. If there is still only 1 bar or
1 bar blinking replace the probe.
Sensor Check
Setting the meter to pH‑mV range the user can check the sensor status at any time. The offset
value is the reading in pH 7.01 buffer (@ 25 °C/77 °F). If this reading is outside the range
±30 mV, the electrode is considered “very poor”. The slope value of the sensor is the difference
between readings in pH 7.01 and in pH 4.01 buffers. When the slope reaches the value of about
150 mV, the electrode is considered “very poor“. When “poor“ or “very poor“, it is recommended
to replace it with a new one.
Note: To ensure reliable readings, the electrode must be cleaned with cleaning solution before
measuring the offset and the slope.