Apera Instruments ZenTest PC60-Z User manual

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SKU:AI3719
ZenTest™ PC60-Z Smart 7-in-1 Tester
(pH/Cond./TDS/Salinity/Resistivity/ORP/Temp.)
Instruction Manual
APERA INSTRUMENTS (Europe) GmbH
www.aperainst.de

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Contents
1. Introduction ....................................................................................................................- 3 -
2. What’s in the Kit..............................................................................................................- 4 -
3. Battery Installation ..........................................................................................................- 4 -
4. Keypad Functions ............................................................................................................- 5 -
5. Preparation before Use....................................................................................................- 5 -
6. pH Calibration..................................................................................................................- 6 -
7. pH Measurement.............................................................................................................- 8 -
8. Conductivity Calibration...................................................................................................- 8 -
9. Conductivity Measurement............................................................................................- 10 -
10. ORP Measurement .....................................................................................................- 11 -
11. Probe Cleaning ...........................................................................................................- 11 -
12. Probe Storage.............................................................................................................- 11 -
13. Parameter Setting.......................................................................................................- 12 -
14. Technical Specifications ..............................................................................................- 13 -
15. Icons and Functions....................................................................................................- 14 -
16. Probe Replacement ....................................................................................................- 14 -
17. Troubleshooting Guide ...............................................................................................- 14 -
18. Warranty....................................................................................................................- 16 -
ATTENTION
•Water droplets are added during production to maintain the moisture of the probe. This is
normal practice and should not be attributed to used product.
•Never use the product when it’s freezing cold. Let it warm to room temperature before using.
•The latest PC60-Z Tester comes with an upgraded probe structure equipped with a sensor
shield that prevents glass bulb breakage from accidental collisions (see picture below).
Users can remove the shield when cleaning the sensor and put it back on after cleaning.

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1. Introduction
Thank you for choosing Apera Instruments PC60-Z Smart Multi-Parameter Tester. Please carefully
read this manual before using the product.
Search “zentest smart” in Apple App Store or Google Play App Store to download the latest
App for your tester. Turn on the Bluetooth of your phone, go to ZenTest™ App, tap on the
upper right corner, then select your tester to connect.
For video tutorials on how to get the most out of ZenTest™, please go to www.aperainst.de
This product is designed with a two-way control on both the tester and ZenTest™ App. Please
refer to the functions available on each platform in the following table. This manual shows you how
to operate the tester without connecting to a smartphone.
Table 1: Funtions on 60-Z Tester and ZenTest® Mobile App
Functions
60-Z Tester
ZenTest Mobile App
Display
LCD display
1. Basic Mode: digital display +calibration
info
Swipe to
switch
among
various
modes
2. Dial Mode: digital display+dial display
3. Graph Mode: digital display+graph
display
4. Table Mode: digital display+real time
measurement and history display
Calibration
Press buttons to
operate
Operate on smartphone following graphic guides
Self-
Diagnosis
Er1 – Er6 icons
Detailed problem analysis and solutions
Parameter
Setup
Press buttons to set
up (except for P7
and P11)
All parameters can be set up in Settings.

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Alarm
The screen turns red
when alarm
triggered; cannot be
setup
Alarm display and alarm values can be preset for each
parameter
Datalogger
N/A
Manual or Auto. Datalogger; notes can be added to saved
data
Data
Output
N/A
Share data via Email
2. What’s in the Kit
3. Battery Installation
Please install batteries according to the following steps. *Please note direction of batteries: All
POSITIVE SIDES (“+”) FACING UP. (Wrong installation of batteries will cause damage to
the tester and potential hazards)
Conductivity Calibration Vials
pH Calibration Vials
PC60-Z Tester
-
+
+
+
+
-
-
-

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4. Keypad Functions
■ Short press------ < 2 seconds ,Long press------- > 2 seconds
5. Preparation before Use
Pull out the battery insulation slip, and take off the probe cap.
Rinse off the probe in pure water (preferably distilled or deionized water. RO water or tap
water is the alternative) , then shake off excess water.
Perform calibration. For pH calibration tutorial, refer to Section 6; for conductivity calibration,
refer to Section 8.
If the tester hasn’t been used for a long time (over 1 month), please soak the probe in the 3M
KCL soaking solution for 15 minutes, then calibrate it before test.
1. When turned off, short press to turn on the tester; long
press to enter parameter setting.
2. In calibration mode or parameter setting, short press to
return to measurement mode.
3. In measurement mode, long press to turn off the tester,
short press to turn on/off backlight.
1.In measurement mode, short press to switch parameter
pH→Cond→TDS→Sal→Res
2.In measurement mode, long press to turn on/off
Bluetooth® receiver. When turned on, will be flashing;
when connected to smartphone, will stay on.
3.In parameter setting, short press to change parameter
(Uni-directional).
1. Long press to enter calibration mode.
2. In calibration mode, short press to confirm calibration.
3. In measurement mode, when automatic lock is turned off,
short press to manually lock or unlock readings.
Battery Cap
Buttons
Probe
PC60-DE
Probe
Probe Cap
LCD Display
pH Sensor
Cond/TDS/Sal/Res Sensor
Probe Ring

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6. pH Calibration
Short press to turn on the meter; rinse the probe in distilled
water, Shake off excess water
Pour certain amount of pH 7.00 and pH 4.00 buffer solution into the
corresponding calibration bottles (to about half volume of the bottle);
Long press to enter calibration mode; Short press to exit.
Insert the probe into pH 7.00 buffer solution, make a quick stir, and
hold still. When the reading is stabilized ( stays on the LCD screen), short press to
complete 1st point calibration. After calibration is completed, the tester will return to
measurement mode. Icon will appear at the bottom left of the LCD screen. indicating a
successful 1st point pH calibration.
To calibrate 2nd point, use 4.00 pH buffer and repeat Step 6.3 to 6.4 (Do NOT turn off the
tester after you finish pH 7 calibration). will display next to , indicating a successful 2-
point pH calibration (low and middle points).
If necessary (target pH>8.00), calibrate 3rd point using 10.01 standard pH buffer and repeat
Step 6.3 to 6.4, will show up next to and , indicating a successful 3-point
calibration (high, low, and middle points).
Notes about Calibrationhe
1) The 1st point calibration must be 7.00 pH. Perform the 2nd and 3rd point calibrations (4.00,
10.01, 1.68, or 12.45) immediately after the 1st point calibration is finished. Do NOT turn off
the meter before you calibrate 2nd or 3rd point. Otherwise, you will need to restart the
calibration process with 7.00 pH first.
2) The pH 4.00 and 7.00 buffer solutions poured into the calibration vials can be used for up to 10
times as long as they are not contaminated and the bottles are capped when not in use. pH
10.01 can only be used for up to 5 times as it will lose its accuracy much faster. After that,
replace the buffer solutions in the calibration vials with new ones to keep the accuracy.
Keeping the freshness and cleanliness of calibration buffers is essential for accurate pH
measurement.
3) The tester can perform 1 to 3 points of automatic calibration and can recognize 5 types of pH
standard solutions. For details, please refer to the following table:
Calibration
USA Series
NIST Series
Indication icon
Recommended
1-point
7.00 pH
6.86 pH
Accuracy
requirement ≥ 0.1
pH
2-pt
Option
A
1st pt: 7.00 pH
2nd pt: 4.00 pH or
1.68 pH
Option
A
1st pt: 6.86 pH
2nd pt: 4.01 pH or 1.68
pH
Range < 7.00 pH
Option
B
1st pt: 7.00 pH
2nd pt: 10.01 pH or
12.45 pH
Option
B
1st pt: 6.86 pH
2nd pt: 9.18 pH or
12.45 pH
Range >7.00 pH
3-pt
1st pt: 7.00 pH
2nd pt: 4.00 or 1.68 pH
3rd pt: 10.01 or 12.45 pH
1st pt: 6.86 pH
2nd pt: 4.01 or 1.68 pH
3rd pt: 9.18 pH or 12.45 pH
Range: 0 to 14.00
pH

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6.8 For the self-diagnosis information, please refer to the table below:
Symbol
Self-Diagnosis
information
Potential problems and how to fix
The pH calibration
solution cannot be
recognized by the meter.
1. Make sure the probe is fully immersed in the
calibration solution.
2. Check if calibration solution is expired or polluted.
3. 1st point of pH calibration must be pH 7.00 or
6.86. See 6.2 (1).
4. Please check whether pH electrode is damaged
or broken. If so, please replace with a new one.
5. The glass bulb or junction is severely
contaminated. Please use a soft brush with soap
water to clean it thoroughly. Then soak it in 3M
KCL 3-5 hours before performing calibration
again.
Is pressed before
measurement is fully
stable
Wait for to come up and stay on screen
before pressing
During calibration,
readings being unstable
for over 3 minutes
1. Please check whether pH electrode is damaged
or broken. If so, please replace with a new one.
2. The glass bulb or junction is severely
contaminated. Please use a soft brush with soap
water to clean it thoroughly. Then soak it in 3M
KCL overnight before performing calibration again.
3. The electrode is aged (used for over a year and
has a much slower response). A replacement is
needed.
pH electrode zero
electric potential out of
range
(<-60mV or >60mV)
1. Check whether pH buffer solutions comply with
the USA or NIST standard.
2. Check whether pH buffers are expired or
contaminated.
3. Please check whether pH electrode is damaged
or broken. If so, please replace with a new one.
4. The electrode is aged (used for over a year and
has a much slower response). A replacement is
needed.
5. The electrode is invalidated (Er4/Er5 repetitively
appears, and problems 1, 2, 3 are excluded). A
replacement is needed.
pH electrode slope out of
range (<85% or >110%)
The calibration reminder is
triggered. It’s time to
perform a new pH
calibration
Perform pH calibration or cancel calibration reminder in
ZenTest App settings.

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7. pH Measurement
How to take pH measurements
Short press to turn on the tester. Rinse the probe in distilled water,
shake off excess water. Insert the probe in your sample solution, make a
quick stir and hold still. Record the reading when it is stabilized (
appears and stays on screen).
Pure Water pH Measurement
When testing pure water like tap water, drinking water, RO water and
distilled water, it will take longer for the readings to get fully stabilized
(typically 1-5 minutes). Please be patient. If still not working, add Apera 3M KCL (AI1107) to your
pure water at the ratio of 1:1000 (e.g. 1 ml KCL to 1000 ml water) to accelerate stabilization while
minimizing pH change. If the accuracy is not meeting your requirement, please contact us at
[e-mail] to find the specialized meter designed for pure water pH test.
8. Conductivity Calibration
How to calibrate
1) Power on the tester. Press key to switch to conductivity measurement mode (Cond). Rinse
the probe in distilled water and dry it.
2) Pour certain amount of 1413μS/cm and 12.88mS/cm conductivity calibration solution into
corresponding calibration bottles (to about half volume of the bottle).
3) Long press key to enter calibration mode, (screen turns green).
4) Dip the probe into 1413 μS/cm conductivity calibration solution, stir gently and hold still. When
the reading is fully stabilized ( stays on screen), short press to start one-point
calibration, the tester returns to measurement mode and will appear at the bottom left of
the screen, indicating a successful 1st point conductivity calibration.
5) If needed (your target conductivity level is greater than 2 mS or 2000 μS), insert the probe into
the 12.88 mS conductivity calibration solution. Follow the steps in 8.1.3 to 8.1.4 to complete the
2nd point of calibration using the 12.88 mS standard solution. will appear next to ,
indicating a successful 2-point conductivity calibration.
Conductivity Calibration Notes
The tester can calibrate 84μS, 1413 μS/cm and 12.88 mS/cm conductivity calibration solution. User
can conduct 1 to 3 points calibration. Refer to the table below. Usually calibrating the tester with
1413 μS/cm conductivity buffer solution alone shall meet the testing requirement.

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Calibration Indication Icon
Calibration Standards
Measuring Range
84 μS/cm
0 - 200 μS/cm
1413 μS/cm
200 - 2000 μS/cm
12.88 mS/cm
2 – 20 mS/cm
For conductivity calibration solutions, we recommend that users replace new solutions after 5 times
of use to keep the standard solution’s accuracy. Do NOT pour the used calibration solutions back
into the solution bottles in case of contamination.
For the self-diagnosis information, please refer to the table below:
Symbol
Self-Diagnosis information
How to fix
The meter cannot recognize the
conductivity standard solutions.
1. Make sure the probe is fully submerged in
the solution.
2. Check if the standard solution is expired or
contaminated.
3. Check if the conductivity electrode (two
black rods) is damaged.
4. Check if the conductivity electrode is
contaminated. If so, please use a soft brush
with warm water to clean up.
Is pressed before
measurement is fully stable (
comes up and stays)
Wait for to come up and stays on screen
before pressing
During calibration, readings being
unstable for over 3 minutes
1. Shake the probe to remove the air bubbles
on the surface of the black rods
2. Check if the conductivity electrode is
contaminated. If so, please use a soft brush
with warm water to clean up.
3. Soak the probe in 12.88mS/cm solution for
10 minutes, then rinse with distilled water.
The calibration reminder is
triggered. It’s time to perform a new
conductivity calibration
Perform conductivity calibration or cancel
calibration reminder in ZenTest settings.

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9. Conductivity Measurement
How to Measure Conductivity, TDS, Salinity, and Resistivity
Short press to turn on the tester. Rinse the probe in distilled water and dry it. Dip the probe
into your sample solution, make a quick stir, and hold still. Record the reading after it is fully
stabilized ( comes up and stays). Press to switch from conductivity to TDS, salinity, and
resistivity.
Unit Conversion
a) 1000 µS/cm= 1 mS/cm = 1 EC (In conductivity mode, the unit will automatically turn from µS
to mS if the reading is greater than 1999 µS, meaning you will only see 2.XX mS instead of
2XXX µS)
b) 1000 ppm = 1 ppt (In TDS mode, the unit will automatically turn from ppm to ppt if the
reading is greater than 999 ppm, meaning you will only see 1.XX ppt instead of 1XXX ppm)
c) The TDS and Salinity values are converted from the conductivity values via a certain
conversion factor. TDS and conductivity is linear related, and its conversion factor is 0.40 to
1.00. Adjust the factor in parameter setting P5 based on the requirements in different
industries. The factory default setting is 0.71.
d) Salinity and conductivity is linear related, and its conversion factor is 0.5.
e) The tester only needs to be calibrated in Conductivity mode.
f) Conversion Example: if conductivity measurement is 1000µS/cm, then the default TDS
measurement will be 710 ppm (under the default 0.71 conversion factor), and the salinity be
0.5 ppt. If TDS conversion rate is changed to 0.5, then the TDS measurement will be 500
ppm.
Temperature compensation factor
The default setting of the temp. compensation factor is 2.0%/˚C. User can adjust the factor based
on test solution and experimental data in parameter setting P10. The following table is some
common examples for setting up the temp. compensation factor.
Solution
Temperature
compensation factor
Solution
Temperature
compensation factor
NaCl
2.12%/˚C
10% Hydrochloric acid
1.32%/˚C
5% NaOH
1.72%/˚C
5% Sulfuric acid
0.96%/˚C
Dilute ammonia
1.88%/˚C

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10.ORP Measurement
ORP stands for Oxidation-Reduction Potential, measured in mV. It’s also called redox. ORP is a
measure of the cleanliness of water & its ability to break down contaminants. A separate ORP probe
(ORP60-DA) needs to be installed to be able to measure ORP.
Power on the PC60-Z tester, unscrew the original probe, and install the ORP60-DA probe, then the
tester will automatically switch to ORP measurement mode (Refer to Section 14 for how to replace
a probe).
Rinse the probe in distilled water and dry it. Dip the probe in sample solution, shake for a few seconds,
and allow it to stand still. Get the ORP readings after appears and stays on screen.
11.Probe Cleaning
1) The tester is only as accurate as the probe is clean. Always thoroughly rinse off the probe before
and after each measurement with pure water in a container or with a wash bottle.
2) For tough contaminants, detach the sensor shield, soak the probe in Apera probe cleaning
solution (AI1166) or detergent water for 30 minutes. Then use a soft brush to remove the
contaminants. Afterwards, soak the probe in 3M KCL soaking solution for at least 1 hour. Rinse it
off, then re-calibrate the tester before using again.
12.Probe Storage
1) Under regular usage (daily or weekly use), make sure the probe cap is wet, and tightly close the
cap with the O-ring.
2) For long-term storage (you are not going to use the product for a while), add 3M KCL soaking
solution to the Fill line in the probe cap and store the probe in it. Close on the probe cap tightly
with the O-ring.
3) If you find white crystals inside or outside the probe cap, it is perfectly normal. It is the 3M KCL
soaking solution that crystalizes over time by its nature. Just rinse them off and add in new soaking
solution. This chemical is not poisonous nor dangerous, and the probe’s performance will not be
affected at all.
4) NEVER store the probe in pure water like tap, RO, distilled, or deionized water as they could
damage the pH probe. If this happens, immediately soak the pH probe Apera 3M KCL soaking
solution overnight, then re-calibrate it before using. Pure water is only for rinsing the probe.

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13.Parameter Setting
Table of Settings
Parameter Setting
1) When the meter is turned off, long press to enter parameter setting →short press to
switch P01-P02… →P14. Short Press , parameter flashes → short press to adjust
parameter → short press to confirm →Short press to exit parameter setting and go
back to measurement mode.
2) Auto. Lock (P02) – Users can set the auto lock time from 5 to 20 seconds. For example, if 10
seconds is set, when the measured value is stable for more than 10 seconds, the measured value
will be automatically locked, and the HOLD icon will be displayed. Short press to release the
lock. When the setting is "Off", the Auto. lock function is turned off, that is, the measured value
can only be manually locked. Short press to lock or unlock the measured value. The HOLD
icon will be displayed when reading is locked.
3) Auto. Backlight (P03) ─ Users can set the automatic backlight time for 1 to 8 minutes. For
example, if 3 minutes is set, the backlight will turn off automatically after 3 minutes; when the “Off”
is set, the auto. backlight function will be turned off, and short press to manually turn the
backlight on or off.
Symbol
Parameter Setting Contents
Content
Factory Default
P1
Temperature Unit
˚C – ˚F
˚F
P2
Select automatic lock
5-20 seconds –Off
Off
P3
Automatic Backlight Off
1-8 minutes –Off
1
P4
Automatic Power Off
10-20 minutes –Off
10
P5
pH Buffer Series Selection
USA –NIST
USA
P6
pH Resolution
0.1 –0.01
0.01
P7
pH Calibration Reminder
H-hours D-Days (set up in
ZenTest App)
/
P8
pH back to factory default
No –Yes
No
P9
Conductivity Reference
Temperature
15 ˚C to 30 ˚C
25 ˚C
P10
Temp. Compensation Coefficient
0 to 9.99
2.00
P11
Conductivity Calibration Reminder
H-hours D-Days (set up in
ZenTest App)
/
P12
Conductivity Back to Factory
Default
No –Yes
No
P13
TDS Factor
0.40 to 1.00
0.71
P14
Salinity Unit
ppt –g/L
ppt

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4) Auto. Power off (P04) ─ The auto. power off time can be set to 10 to 20 minutes. For example,
if 15 minutes is set, the meter will automatically shut down after 15 minutes if no operation; when
“Off” is set, the auto. power off function will be turned off. Long press to manually shut down
the meter.
5) pH Calibration Reminder (P07) and Conductivity Calibration Reminder (P11) – set X hours
(H) Or X days (D) in ZenTest mobile app – settings – Parameter – pH – Calibration Reminder. On
the meter, you can only check the values that’s been set up on ZenTest App. For example, if 3
days is set up, the Er6 icon (see Figure-4) will appear in the lower right corner of the LCD screen
in 3 days to remind you to perform calibration, also in the ZenTest App there will be a pop-up
reminder. After calibration is finished or the reminder setting is cancelled in the ZenTest App, the
Er6 icon will disappear.
6) pH Back to Factory Default (P08) and Conductivity Back to Factory Default (P12) – Select
“Yes” to recover instrument calibration to theoretical value. This function can be used when
instrument does not work well in calibration or measurement. Calibrate and measure again after
setting the instrument back to factory default.
14.Technical Specifications
pH
Range
-2.00 to 16.00 pH
Resolution
0.01 pH
Accuracy
±0.01 pH ±1 digit
Calibration Points
1 to 3 points
Auto. Temperature
Compensation
0 –50˚C (32 – 122˚F)
Conductivity
Range
0 to 199.9 μS, 200 to 1999 μS, 2 to 20.00 mS/cm
Resolution
0.1/1 μS, 0.01 mS/cm
Accuracy
±1% F.S
Calibration Points
1 to 3 points
TDS
Range
0.1 ppm to 10.00 ppt
TDS Factor
0.40 to 1.00
Salinity
Range
0 to 10.00 ppt
Resistivity
Range
50Ω to 20MΩ
ORP (mV)
Range
-1000 mV to 1000 mV
Accuracy
±0.2% F.S
Temperature
Range
0 to 50˚C (32-122˚F)
Accuracy
±0.5˚C

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15.Icons and Functions
16.Probe Replacement
To replace a probe:
1) Take off the probe cap; 2) Screw off the probe ring 3) Unplug the probe; 4)
Plug in the new replacement probe (pay attention to the probe’s position); 5)
Screw on the probe ring tightly. Soak the probe in 3M KCL for 5-15 minutes.
Then perform calibration before testing.
The replacement probes that are compatible with PC60-Z are:
•PC60-DE (Default pH/cond. Probe),
•PH60-DE (Regular pH glass bulb probe), PH60S-DE (Spear pH
probe for solids/semi-solids pH testing), PH60F-DE (Flat pH probe for surface pH testing),
•EC60-DE (Conductivity probe)
•ORP60-DA (ORP Probe).
*Probes don’t last forever. Every probe will eventually age and fail even if you don't use it that often.
The typical service life of Apera probes is 12-24 months depending on the frequency of usage and
how well you keep it clean and properly stored. We recommend replacing your probe every 1 to 2
years to ensure the best performance.
17.Troubleshooting Guide
Calibrated points
Self-Diagnosis
Symbol
Er1, Er2, Er3, Er4,Er5, Er6
Stable reading
indicator
Waterproof Rating
IP67, floats on water
Reading Lock
HOLD
Power
DC3V, AAA batteries*4
Bluetooth Signal
Battery Life
＞200 Hours
Low power reminder
Backlight
White: Measurement;
Green: Calibration; Red: Alarm
Auto. Power Off
Automatically power off if no operation for 10 minutes
Dimension/Weight
Instrument：40×40×178mm/133g; case：255×210×50mm/680g;
Graph-3
LCD Display
Graph-4
pH calibration reminder
Graph-5
pH alarm triggered

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Trouble
Reason
How to fix
Cannot
calibrate
Incorrect standard
solutions
Power on the meter, calibrate pH 7 first, then pH 4.
After pH 4 is calibrated, if you want to calibratepH 7
again, you need to reboot the tester.
Poor quality standard
solutions
Replace with fresh and clean standard calibration
solutions made by legitimate scientific instrument
manufacturers.
Contaminated probe
Clean the probe with Apera probe cleaning solution
or detergent water.
Aged probe
Replace the probe.
Dried-out probe
Soak the probe in 3M KCL solution for at least 15
minutes.
Probe is not fully
submerged in the solution
Make sure the probe is fully immersed in the
solution at least 1 inch deep.
Air bubbles around the
sensor
Make a quick stir in the solution to remove air
bubbles.
Reading is
always slowly
changing, won’t
stabilize
Contaminated probe
Clean the probe with Aprea’s cleaning solution or
detergent water.
Clogged junction
Clean the probe with Aprea’s cleaning solution,
then soak it in 3M KCL soaking solution overnight.
Aged probe
Replace the probe.
Testing pH of low iconic
strength solutions like tap
water, drinking water, RO
water
Be patient, wait for 1-5 minutes to reach a fully
stabilized reading. If still not stabilizing, add 1ml of
3M KCL solution to 1000ml of test solution (or 1
teaspoon to 1 gallon).
Display similar
readings in any
solutions or
always display
7.0 pH
Broken probe
If you don’t find any visible damage of the probe,
contact us for warranty fulfillment; If there is visible
damage, replace the probe.
Reading keeps
jumping
Probe is not fully
submerged in the solution
Make sure the probe is fully immersed in the
solution at least 1 inch deep.
Air bubbles around the
sensor
Make a quick stir in the solution to remove air
bubbles.
Probe is not properly
connected, or the pin
connector is broken.
Check the probe’s connector, make sure it’s not
broken and is correctly connected. Align the probe
and instrument correctly before plugging in. Never
force it. Ensure that the probe connector is not
exposed to air too long.
Calibration is
successful, but
reading is not
accurate
Aged probe
Replace the probe.
Air bubbles around the
sensor
Make a quick stir in the solution to remove air
bubbles.
Clogged junction
Clean the probe with cleaning solution, then soak it
in 3M KCL soaking solution overnight.
Comparison with other
testers, test strips, or
drop tests
To compare with other testers, make sure to
perform a 2-point calibration for all testers in the
same standard, then test a 3rd point. Whichever
gives more accurate reading is the more accurate
one. Test strips or drop tests’ accuracy is not
comparable to pH meters ‘.

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18.Warranty
We warrant this instrument to be free from defects in material and workmanship and agree to repair
or replace free of charge, at option of APERA INSTRUMENTS (Europe) GmbH, any malfunctioned
or damaged product attributable to responsibility of APERA INSTRUMENTS (Europe) GmbH for a
period of TWO YEARS (SIX MONTHS for the probe) from the delivery. This limited warranty does
NOT cover any damages due to: accidental damage, unauthorized repair, normal wear and tear, or
external causes such as accidents, abuse, or other actions or events beyond our reasonable control.
APERA INSTRUMENTS (Europe) GmbH
Wilhelm-Muthmann-Straße 18, 42329 Wuppertal, Germany
Contact: [e-mail] | www.aperainst.de |Tel. [phone]