Apera Instruments TN400 User manual

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TN400 Portable Turbidity Meter
Instruction Manual
APERA INSTRUMENTS LLC
aperainst.com

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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 ........................................................................... - 12 -
5.4 Notes for Measurement........................................................................ - 12 -
6Warranty ................................................................................... - 13 -
7Replacement Parts..................................................................... - 14 -

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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 the turbidity of an aqueous
sample both in laboratory and in the field.
The instrument is an outstanding combination of the most advanced electronic technology and software
design. With built-in microprocessor chips, elegant design, easy to use, the meter has the following
remarkable characteristics:
⚫Smart functions, such as automatic calibration, operating instructions, automatic power-off, low
voltage display, etc.
⚫Large TFT color screen, with blue background in measuring mode, green background in calibration
mode, and text and graphics in operational directive.
⚫Operation guidance and reminders in the process of calibration, measurement and parameter setting.
⚫Average measurement mode automatically takes 10 times consecutive readings, calculate and
display the average. It improves the accuracy of the measurement, especially suitable for sample
solutions with rapid settling and continuous measurement changes.
⚫The instrument meets IP67 water-resistant grade and is suitable for use in harsh environments.
⚫Everything comes in a rugged carrying case, including accessories such as calibration solutions, test
vials, and more, convenient for use and carry.

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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 to 90% at 30°C, 0 to 80% at 40°C, 0 to 70% at 50°C, no condensation
Storage Condition
Instrument: -40~60℃ (-40~140℉)
Calibration Solution: 5~30℃ (41~86℉)
Instrument sealing grade
IP67
Certificates
CE
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
①
Flip cover of the sample vial holder (Close the
cover when measuring)
⑥
Dust proof plug (Take off the plug when
measuring)
②
Housing
⑦
Sample vial holder
③
Display
⑧
Calibration vials or sample vials
④
Keypad
⑨
Positioning mark (Align the mark with the
mark on the calibration vial or sample vial)
⑤
Battery cover
Diagram-1
⑨
⑥
⑦
⑧
⑤

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3.2 Meter and Accessories
3.3 Display Mode
Measuring
Mode
Calibration
Mode
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
Diagram-2
①
②
③
④
⑤
⑧
⑦
⑥
⑨
①— Measurement mode
②— Measurements and unit
③— Operational guide
④— Battery icon
①— Calibration solution
②— Measurements and unit
③— Progress bar
④— Operational guide

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Calibration
Menu
3.4 Keypad
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
Diagram- 3
①— Calibration mode
②— Standard values
③— Operation guide
④— Finish calibration indicator

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icon displays to ensure measuring accuracy; when icon displays, the battery must be
replaced, otherwise the instrument can't 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.
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 ofthe 0.0 NTU solution
vial can be opened. Once the solution is invalidated, users can replace the 0.0 NTU calibration
solution or laboratory distilled water. The AMCO 0.0 NTU calibration solution can be purchased from
the supplier; For the remaining 4 calibration solutions, their vial caps are sealed and 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 7 Replacement Parts.
b) Replace zero turbidity solution
⚫Replace with 0.0 NTU calibration solution: open the vial cap, pour out the original solution, add
1/2 distilled water, close the cap and shake the vial to rinse it and pour out the water. Repeat it
3 times. Shake off the distilled water in the vial. Pour in new 0.0 NTU calibration solution and
tighten the vial cap.
⚫Replace with laboratory distilled water: open the vial cap, pour out the original solution, add 1/2
distilled water, close the cap and shake the vial to rinse it and pour out the water. Repeat it 3
times. Shake off the distilled water in the vial. Pour in new laboratory distilled water and tighten
the vial cap.
⚫The accuracy of 0.0 NTU calibration solution and laboratory distilledwater is same. But 0.0 NTU
calibration solution has 6 to 12 months of shelf-life, distilled water can be contaminated easily
after air contact and lose the validity in a couple of days.
AMCO 0.0 NTU solution is provided in factory configuration. For purchase details, please refer to
Section 7 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 micro-fiber cloth to
evenly distribute the silicone oil on the surface so as to cover smudges or scratches, which helps
light scattering. But please pay special attention to the following points:

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①The silicone oil applied should not be too much. After wiping with micro-fiber 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
The U.S EPA approved AMCO polymer standard calibration solution is very uniform and stable.
It does not precipitate, drift or condense. It can be used directly without shaking or flipping the
vial (to make the solution even). For polymer calibration 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 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 make the measurement unstable. Operating
experience is important in using Formazin calibration solutions.
4.2 Calibration Procedure (Take 0 NTU and 20 NTU as an example)
1) Instrument warm up: Power on the instrument, and then wait for 3 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.

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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.
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:
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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b) Calibration point selection: The instrument has been calibrated at full range before leaving the
factory. Users can select2 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 turbiditymeasurements (measurement lessthan 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 bydifferent
vials, thus achieving higher accuracy. For example, add 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 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 note that the diluted Formazin standard is
unstable. Please make sure to use freshly made Formazin standard to ensure calibration accuracy.
5 TURBIDITY MEASUREMENT
5.1 Sample Vial Handling
1) There are 6 sample vials contained in the case, marked 1#~6# on the cap and bottom of the vial.
Please note the number of sample vial should be same as that of vial cap, and do not mix up. Please
always use 1#~2# sample vial to measure samples with turbidity less than 2 NTU. 3#~6# sample vials
are used for measurement of other solutions.
2) Sample vials have been meticulously cleaned and disinfected before they leave factories. They can
be used directly for the first time. Before subsequent uses, sample vials should be thoroughly cleaned:
wash the interior and exterior of the vial in a detergent solution. Repeatedly rinse with clean distilled
water or deionized water. Rinse sample vial with sample solution twice. Fill sample vial with sample
solution then screw the vial cap tightly.
5.2 Measurement Preparation
1) Collect sample solution in a clean container, fill sample solution to the 4/5 position of the sample vial

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(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
Press button, the display shows progress bar (see diagram-6). It will display measured value
after 8 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.
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
fingerprintson thesurface of the vial. Its surface should be applied with a drop of silicone oil be wiped
with a micro-fiber 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
Diagram- 4
Diagram- 5
Diagram 6

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will cause big error to turbidity measurement. So, the vial should be left 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.
⚫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 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, LLC, any malfunctioned or damaged
product attributable to the responsibility of APERA INSTRUMENTS, LLC 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 maintenance, modifications, combination or use with any products, materials,
processes, systems or other matter
⚫Unauthorized repair
⚫External causes such as accidents, abuse, or other actions or events beyond our reasonable
control.

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7 REPLACEMENT PARTS
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
APERA INSTRUMENTS, LLC
Address: 6656 Busch Blvd, Columbus Ohio 43229
Tel: [phone]
Email: [e-mail]
Website: https://aperainst.com