Apera Instruments TN400 User manual

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TN400 Portable Turbidity Meter
Instruction Manual
APERA INSTRUMENTS (Europe) GmbH
www.aperainst.de

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Table of Contents
1Overview................................................................................................................... - 3 -
2Technical Specifications ........................................................................................... - 4 -
2.1 Technical Parameters....................................................................................................- 4 -
3Instrument Description.............................................................................................. - 5 -
3.1 Instrument Overview......................................................................................................- 5 -
3.2 Meter and Accessories ..................................................................................................- 6 -
3.3 Display Mode.................................................................................................................- 6 -
3.4 Keypad..........................................................................................................................- 7 -
3.5 Power Supply ................................................................................................................- 7 -
4Meter Calibration ...................................................................................................... - 8 -
4.1 Preparation for Calibration.............................................................................................- 8 -
4.2 Calibration Procedure (Take 0 NTU and 20 NTU as an example)..................................- 9 -
4.3 Notes for Calibration....................................................................................................- 10 -
5Turbidity Measurement ............................................................................................- 11 -
5.1 Sample Vial Handling ..................................................................................................- 11 -
5.2 Measurement Preparation ...........................................................................................- 11 -
5.3 Measurement Modes...................................................................................................- 11 -
5.4 Notes for Measurement ...............................................................................................- 12 -
6Replacement parts ................................................................................................. - 13 -
7Warranty ................................................................................................................. - 13 -
V5.3

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1 OVERVIEW
Thank you for purchasing Apera Instruments TN400 Portable Turbidity Meter (hereafter
referred to as the instrument).
The instrument uses infrared light emitting diode (LED 860±30nm) as the light source and 90°
scattering method, which is compliant with ISO 7027 and DIN EN 27027 standards for the
determination of turbidity for water solutions. TN400 allows you to measure turbidity in a reliable and
simple manner wherever you are.
Main features and functions
⚫Large TFT color screen with clear on-screen instructions for easy operation.
⚫Average measurement mode automatically takes 10 sets of readings consecutively and
display the average. It improves the accuracy of the measurement, especially suitable for
sample solutions with rapid settling and continuous measurement changes.
⚫U.S. EPA certified, non-toxic, easy-to-use polymer standard calibration solutions
⚫Rugged design, suitable for use in harsh environments.
⚫Everything comes in a carrying case, including accessories such as calibration solutions,
sample vials, and more.

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2 TECHNICAL SPECIFICATIONS
2.1 Technical Parameters
Measuring Method
ISO 7027 and DIN EN 27027
compliant nephelometric method (90°)
Light Source
Infrared light emitting diode (860±30nm)
Measuring Range
0 – 1000 NTU, automatic range selection:
0.01 – 19.99 NTU
20.0 – 99.9 NTU
100 – 1000 NTU
Accuracy
≤ ±2 % of reading + stray light
Repeatability
≤ ± 1% of reading or 0.02 NTU (FTU), the greater of the two
Resolution
0.01 / 0.1 / 1 NTU (FNU)
Stray Light
≤0.02 NTU (FNU)
Calibration Standards
AMCO Polymer or Formazin Solution:
0, 20, 100, 400 and 800 NTU (FNU)
Detector
Silicon photovoltaic
Measurement Mode
Normal measurement and average measurement mode
Display
TFT color screen
Sample Vials
Φ25×60 mm, high borosilicate glass with lid
Sample Volume
18 ml
Power Supply
4× AA Alkaline Batteries
Operating Condition
Temperature: 0 to 50°C（32°F to 122°F）；Relative humidity：
0 – 90% at 30°C, 0 – 80% at 40°C, 0 – 70% at 50°C, no
condensation
Storage Condition
Instrument: -40 to 60°C (-40 to 140°F)
Calibration Solution: 5 to 30°C (41 to 86°F)
Instrument sealing
grade
IP67
Certificates
CE and RoHS
Limited Warranty
2 years
Dimension and Weight
Meter: (90×203×80) mm/385g
Test Kit: (310×295×110) mm/1.5kg

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3 INSTRUMENT DESCRIPTION
3.1 Instrument Overview
Diagram-1
①Flip cover of the sample vial holder
(Close the cover when measuring)
②Housing
③Display
④Keypad
⑤Battery cover
⑥Dust proof plug (Take off the plug
when measuring)
⑦Sample vial holder
⑧Calibration vials or sample vials
⑨Positioning mark (Align the mark with
the mark on the calibration vial or
sample vial)
⑨
⑥
⑦
⑧
⑤
①
②
③
④

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3.2 Meter and Accessories
Diagram-2
3.3 Display Mode
Measuring
Mode
①Measurement mode
②Measurements and unit
③Operational guide
④Battery icon
Calibration
Mode
①Calibration solution
②Measurements and unit
③Progress bar
④Operational guide
Calibration
Menu
①Calibration mode
②Standard values
③Operation guide
④Finish calibration indicator
①
Calibration Solutions：
0.0, 20.0, 100, 400, 800 NTU
②
Carrying case
③
TN400 Turbidimeter
④
Microfiber cloth
⑤
Screwdriver
(to remove battery cover)
⑥
Silicone oil (10 ml)
⑦
AA Alkaline battery×4
⑧
Sample vial×6
⑨
Instruction manual
①
②
③
④
⑤
⑧
⑦
⑥
⑨

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3.4 Keypad
Diagram- 3
Key
Functions
⚫Power on/off
⚫The meter will automatically shut off 10 mins after last key press
⚫In measurement mode: press to enter calibration mode
⚫In calibration mode: press to exit calibration mode
⚫In measurement mode: long press to switch measurement units NTU-FTU
⚫In measuring mode: Short press the key to perform single-shot measurement;
long press the key to perform continuous measurement
⚫In calibration mode: press the key to confirm the calibration.
⚫In calibration mode, press the key to select standard solution.
3.5 Power Supply
1. The instrument adopts 4 pieces of AA alkaline battery. Make sure there is no mixture of new & old
batteries or different models of batteries.
2. Battery capacity indication
Battery capacity icon: please replace new batteries when
icon displays to ensure measuring accuracy; when icon displays, the battery must be
replaced, otherwise the instrument cannot work properly. To extend battery life, user can setup
auto-power off timer in Parameter Setup P6 according to usage requirements
3. Use the screwdriver to remove the four screws on the battery cover and open the battery cover.
Insert 4 pieces of AA alkaline battery. Please make sure the polarity is correct. Put on the battery
cover and screw tightly.

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4 METER CALIBRATION
4.1 Preparation for Calibration
a) Calibration Point
The instrument has 5 calibration points: 0 NTU, 20 NTU, 100 NTU, 400 NTU, and 800 NTU.
Among them, 0 NTU point uses AMCO 0.0 NTU calibration solution or laboratory distilled water,
and the remaining 4 calibration points use AMCO polymer solutions. Note that the cap of the 0.0
NTU solution vial can be unscrewed. After the solution is invalidated, users can replace the 0.0
NTU calibration solution or use fresh laboratory distilled water. The AMCO 0.0 NTU calibration
solution refill can be purchased from the supplier; For the remaining 4 calibration solutions, their
vial caps cannot be opened. Simply dispose the solutions after they are expired and buy new
ones from your supplier to replace. See the detail in Section 6 Replacement Parts.
b) Replace zero turbidity solution
⚫Open the vial cap, pour out the original solution, add 1/2 distilled water, screw on the cap and
shake the vial to rinse it off and pour out the water. Repeat it 3 times. Shake off the distilled
water in the vial. Pour in new AMCO 0.0 NTU calibration solution or fresh laboratory distilled
water and close the vial cap.
⚫AMCO 0.0 NTU calibration solution has 6 to 12 months of shelf-life, distilled water is only valid
for a couple of days. AMCO 0.0 NTU solution is provided in the default kit. For purchase
details, please refer to Section 6 Replacement Parts.
c) Clean vial surface
Apply a small drop of silicone oil on the surface of the vial and wipe it off with a lint-free cloth to
evenly distribute the silicone oil on the surface in order to cover smudges and scratches, which
helps light scattering. But please pay attention to the following points:
①The silicone oil applied should not be too much. After wiping with lint-free cloth, please wipe
with filter paper or high-quality tissue paper to clean off. Excessive residual silicone oil on the
vial surface will affect the measurement accuracy.
②It's not necessary to use silicone oil for each calibration and measurement. Apply silicone oil
every several days or once a week. In between, just clean the surface with filter paper or
high-quality tissue paper.
③Clean the calibration vial and sample vial together and keep the steps and actions consistent
to achieve same degree of cleanliness.
④Stability of calibration solutions
⑤The U.S EPA approved AMCO polymer standard calibration solution is very uniform and
stable. It does not precipitate, drift or condense. Generally, it can be used directly without
shaking or flipping the vial (to make the solution even). For AMCO polymer calibration

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solutions that have not been used for a long time, slowly flip the vial twice and let it stand for
2 minutes. Be careful not to shake the solution vigorously, as this will create air bubbles
which will destabilize the measurement; For 0.0 NTU calibration solution, do NOT shake or
flip. If using Formazin calibration solution, as it tends to precipitate easily, each time users
must flip and shake the vial to make the solution even. But sediment can still occur during
tests and would make the measurement unstable. Users need to have rich experience
handling Formazin calibration solutions.
4.2 Calibration Procedure (Take 0 NTU and 20 NTU as an example)
1) Instrument warm up (only required for low-range or high-accuracy measurement):
Power on the instrument, set parameter P2 (continuous measurement time) to 5 times.
Long press to start continuous measurement (don't insert the vial), then wait
for 3 to 5 minutes.
2) Open the flip cover and place the 0.0 NTU
calibration vial. Align the arrow on the vial lid with the
one on the sample vial holder and close the flip
cover.
3) Press to enter the calibration menu, the
cursor is at 0 NTU. Press to start calibration.
4) After calibration is done, press to confirm.
The instrument will return to the calibration menu
(see Diagram on the right side). The OK sign
indicates that 0 NTU has been calibrated and
prompt to calibrate 20 NTU.
5) Place the 20.0 NTU calibration vial in the sample
vial holder, press to start 20 NTU calibration.
After calibration is done, press to confirm.
The instrument will return to the calibration menu
(see diagram on the right side). The OK sign
indicates that 20 NTU has been calibrated.

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6) If you want to continue to calibrate 100, 400 and 800 NTU, place the 100 NTU
calibration vial in the sample vial holder and press to calibrate. After
calibration is done, press to confirm; repeat the steps to calibrate 400 NTU
and 800 NTU. After calibration is done, press to return to measurement mode.
7) Press to exit calibration mode, the
instrument will return to measurement mode as
shown in Diagram on the right side.
4.3 Notes for Calibration
a) Calibration point verification: The calibration point can be verified after the calibration is
completed. If the calibration point has a large error, enter the calibration mode and repeat the
calibration. For calibration point accuracy, users can refer to the following standards:
b) Calibration point selection: The instrument has been calibrated at full range before leaving
the factory. Users can select 2 or more points as needed to calibrate, as long as the target
measurement range is in between of the two calibration points. In calibration setup mode, press
or to select the calibration point.
c) Low turbidity calibration requirement
⚫For low turbidity measurements (measurement less than 2 NTU), please test 0.0 NTU
calibration solution. If the accuracy is not meeting your requirements, calibrate the instrument
at 0.0 NTU and 20.0 NTU before test; then use 1#or 2#vial for measurement.
⚫Using the same sample vial to calibrate and measure can eliminate the error caused by
different vials, thus achieving higher accuracy. For example, add laboratory distilled water to
1#vial for zero-point calibration and then add sample solution to 1#vial for measurement.
Note that the test vial should be rinsed thoroughly when changing solutions.
d) High turbidity calibration requirement: For turbidity measurement greater than 2 NTU, it is
recommended to calibrate once a week, or to test a calibration solution close to the sample
Calibration point
Accuracy for reference
0 NTU
≤0.05 NTU
20 NTU
≤±0.2 NTU
100 NTU
≤±2 NTU
400 NTU and 800 NTU
≤±5 NTU

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solution. If the error is large, the instrument needs to be recalibrated.
e) The instrument does not automatically recognize the calibration solution. If the wrong solution is
selected for calibration, the measurement will be completely wrong. To fix this problem, simply
re-calibrate the meter selecting the correct calibration solutions.
f) Place the instrument on a flat and level surface. Do not hold the instrument in hand while
operating.
g) If using Formazin standards for calibration, please make sure to use freshly made Formazin
standard to ensure calibration accuracy.
5 TURBIDITY MEASUREMENT
5.1 Sample Vial Handling
1) 6 sample vials are included in the test kit. The cap is marked with 1#to 6#, and the bottom of the
vial also has the same number. The number of the vial and the cap should always be the same.
*Pay attention that 1#and 2#vials are only for low turbidity solution measurement. (< 2 NTU)
2) The vial has been rigorously cleaned and sterilized. They can be used directly for the first time.
For subsequent uses, follow the steps below to perform a thorough cleaning.
⚫Clean the sample vial inside and outside with detergent → rinse with distilled water or
deionized water multiple times → Rinse the vial twice with the sample solution → Pour the
sample solution into the vial → Close the cap.
5.2 Measurement Preparation
1) Collect sample solution in a clean container, fill sample solution
to the 4/5 position of the sample vial (approximately 18ml), see
Diagram-4, tighten the vial cap.
2) Before measuring, gently shake the sample vial to make sample
solution even and wait for air bubbles to disappear, see
Diagram-5, wait for 2–5 minutes until bubbles eliminate.
3) Wipe the sample vial surface with a microfiber cloth. Ensure that the vial is dry, clean and free
from smudges.
4) Apply 1 drop of silicone oil on the surface of the vial. Wipe with a microfiber cloth to obtain an
even distribution over the entire surface in order to eliminate scratches and smudges and
improve light scattering, see Section 4.1(c) for details.
5.3 Measurement Modes
a) Normal Measurement Mode
Diagram- 4
Diagram- 5

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Press button, the display shows progress bar (seeDiagram-6). It will display measured value
after 10 seconds. Please press button again for repeated measurement.
b) Average Measurement Mode
Long press button, release it until you hear a beep, then the instrument enters average
reading mode. In this mode, the instrument will perform 10 times of continuous measurement,
displaying 1 data every 8 seconds, and will display the average value at the end, see diagram 6. The
average measurement mode can be used for observing the stabilizing process of turbidity, and can
also be used for testing rapid-settling solutions.
Diagram 6
5.4 Notes for Measurement
a) Keep the sample stable: After the vial is placed into the sample cell, it is recommended to wait
for 1 to 2 minutes before calibration, as the solution will experience some shaking when the vial
moves, which may affect measurement accuracy.
b) Sample vial cleaning requirement: Sample vials must be rigorously cleaned and free from
smudges or scratches. When wiping, user should grip the cap and bottom to avoid leaving
fingerprints on the surface of the vial. Its surface should be applied with a drop of silicone oil be
wiped with a lint-free cloth. After that, please clean with filter paper or high-quality tissue paper.
See section 4.1(c) for details.
c) Mixing and Degassing: Samples should not be vigorously shaken or vibrated. It is
recommended that users gently shake the sample vial to make solution evenly distributed. Air
bubbles in solution will cause big error to turbiditymeasurement. So, the vial should beleft stand
still for 2 to 5 minutes to eliminate potential air bubbles before measuring. We recommend using
the same mixing procedure and the same waiting time for degassing before comparing
measurements.
d) Other Requirements
⚫On the premise of ensuring evenly distributed samples, sample solution should be
measured immediately to prevent temperature changing and precipitates from affecting
measurements.

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⚫Avoid sample dilution for measurement as much as possible.
⚫Avoid operating under direct sunlight.
⚫Do not pour solution into the sample vial holder. Sample vials must be used for
measurement.
⚫Please do not wash the sample vial holder as it may damage the optical structure.
6 REPLACEMENT PARTS
7 WARRANTY
We warrant this instrument to be free from defects in material and workmanship and agree to repair
or replace free of charge, at the option of APERA INSTRUMENTS any malfunctioned or damaged
product attributable to the responsibility of APERA INSTRUMENTS for a period of TWO YEARS for
the instrument from the delivery.
This limited warranty does NOT cover any issues due to:
•Accidental damage, improper use, normal wear and tear, transportation, storage, failure to follow
the product instructions, unauthorized modifications or repair, and other external causes or actions
beyond our reasonable control.
APERA INSTRUMENTS (Europe) GmbH
Wilhelm-Muthmann-Straße 18
42329 Wuppertal, Germany
Contact: [e-mail]
Website: www.aperainst.de
Tel. [phone]
Model
Name
Description
Quantity
T500-2
AMCO 0.0 NTU calibration
solution
0.0 NTU/100mL
1 bottle
T200-1
20/100/400/800 NTU
AMCO polymer
Compatible with
TN400&TN480
4 bottles
T500-3
Sample vials with lid
Φ25×60mm，1# – 6#
6 pcs
TN400-S3
Silicone oil
10mL
1 bottle