LaMotte 2020e, 2020i User Instruction
2020e • Code 1979-EPA
2020i • Code 1979-ISO
Version 1.5 • Code 1979-MN • 12-07
e
/i
WARNING! This set contains chemicals
that may be harmful if misused. Read
cautions on individual containers
carefully. Not to be used by children
except under adult supervision
CONTENTS
Introduction............................6
Turbidity ...................................6
WhatisTurbidity?............................6
HowisTurbidityMeasured?........................7
TakingTurbidityWaterSamples......................7
Sample Dilution Techniques .........................7-8
OptionsandSetUp........................8
FactoryDefaultSettings ............................8
ResettoFactoryDefaultSettings ........................8
Turbitity....................................8
SelectingTurbidityUnits ........................8-9
SelectingaTurbidityCalibrationCurve................10-11
Averaging................................11-12
SettingDate&Time............................12-13
SelectingaLanguage.............................14
SettingAutoShutdown............................15
DataLogging.........................16-17
TubePositioningRing.......................18
Analysis&Calibration ......................18
Analysis ..............................19-21
Dilution Procedures ...........................22
PreparationofTurbidity-FreeWater..................22-23
TurbidityStandards...........................24
CalibrationProcedure........................24-28
TestingTips...............................29
Troubleshooting Guide..........................30
ErrorMessages ...............................30
Troubleshooting...............................30
StrayLight..................................31
GeneralOperatingInformation..................30
Overview..................................31
TheKeypad ...............................32-33
The Display & Menus ...........................34-36
NegativeResults...............................35
Tubes....................................36
PCLINK.............................37
Output...................................37
4 CONTENTS
Computer Connection ............................37
BatteryOperation ........................37
ReplacingtheBattery.............................37
Maintenance...........................38
Cleaning................................38
Repairs ................................38
MeterDisposal.............................38
GeneralInformation.......................39
PackagingandDelivery............................39
General Precautions .............................39
SafetyPrecautions..............................39
Limits of Liability ...............................39
Specifications................................40
StatisticalandTechnicalDefinitionsRelatedtoProductSpecifications.......41
ContentsandAccessories...........................42
EPACompliance...............................42
ISOCompliance .............................. 42
CEComplicance...............................42
Warranty ..................................42
CONTENTS 5
INTRODUCTION
TURBIDITY
What is Turbidity?
Turbidity is an aggregate property of the solution, water in most cases. Turbidity is not
specific to the types of particles in the water. They could be suspended or colloidal
matter and they can be inorganic, organic or biological. At high concentrations
turbidity is perceived as cloudiness or haze or an absence of clarity in the water.
Turbidity is an optical property that results when light passing through a liquid sample
is scattered. The scattering of light results in a change in the direction of the light
passing through the liquid. This is most often caused when the light strikes particles in
solution and is scattered backward, sideways and forward. If the turbidity is low much
of the light will continue in the original direction. Light scattered by the particles allows
the particle to be ”seen” or detected in solution. Just as sunlight passing through a
window is a scattered by dust particles in the air, allowing them to be seen.
In the past 10 years, turbidity has become more than just a measure of water clarity.
Because of the emergence of pathogens such as Cryptosporidium and Giardia,
turbidity now holds the key to assuring proper water filtration. In 1998, the EPA
published the IESWTR (interim enhanced surface water treatment rule) mandating
turbidities in combined filter effluent to read at or below 0.3 NTU. By doing so, the
EPA hoped to achieve a 2 log (99%) removal of Cryptosporidium. There is presently
consideration to lower this to 0.1 NTU. The trend has been to check the calibration of
on-line turbidimeters with hand-held field units. The optical design and low detection
limit of the 2020 allow very accurate readings for such calibrations.
The meter also allows the user to choose the units of measure for expressing turbidity.
While nephelometric turbidity unit (NTU) has been the standard for years, FNU
(formazin nephelometric unit) and FAU (formazin attenuation unit) are now being used
in ISO 7027 units. American Society of Brewing Chemists (ASBC) units and European
Brewery Convention (EBC) units allow the brewing industry to check process waters.
How is Turbidity Measured?
Turbidity is measured by detecting and quantifying the scattering of light in water
(solution). Turbidity can be measured in many ways. There are visual methods and
instrumental methods. Visual methods are more suitable for samples with high
turbidity. Instrumental methods can be used on samples with both high and low levels
of turbidity.
Two visual methods are the Secchi Disk method and the Jackson Candle method. The
Secchi Disk method is often used in natural waters. A black and white Secchi Disk is
lowered into the water until it can no longer be seen. It is then raised until it can be
seen again. The average of these two distances is known as the “Secchi Depth”. The
Jackson Candle method uses a long glass tube over a standard candle. Water is
added or removed from the tube until the candle flame becomes indistinct. The depth
of the water measured with a calibrated scale is reported as Jackson Turbidity Units
(JTU). The lowest turbidity that can be determined with this method is about 25 NTU.
There are two common methods for instruments to measure turbidity. Instruments can
measure the attenuation of a light beam passing through a sample and they can
measure the scattered light from a light beam passing through a sample. In the
attenuation method, the intensity of a light beam passing through turbid sample is
6 INTRODUCTION
compared with the intensity passing through a turbidity-free sample at 180° from the
light source. This method is good for highly turbid samples. The most common
instrument for measuring scatter light in a water sample is a nephelometer. A
nephelometer measures light scattered at 90° to the light beam. Light scattered at
other angles may also be measured, but the 90° angle defines a nephelometric
measurement. The light source for nephelometric measurements can be one of two
types to meet EPA or ISO specifications. The EPA specifies a tungsten lamp with a color
temperature of 2,200–3,000 K. The units of measurement for the EPA method are
nephelometric turbidity units (NTU). The ISO specifies a light emitting diode (LED) with
a wavelength of 860 nm and a spectral bandwidth less than or equal to 60 nm. The
units of measurement for the ISO method are formazin nephelometric units (FNU).
The 2020e meets the EPA specification and the 2020i meets the ISO specification.
The nephelometric method is most useful for low turbidity.
The 2020 is a nephelometer that is capable of measuring turbidity by both the
attenuation method and the nephelometric method. It uses a detector placed at 180°
to the light source for the attenuation method. It uses a detector placed at 90° to the
light source for the Nephelometric method. The 2020 also has a third detector that
monitors the intensity of the light source. It uses this detector to improve instrumental
stability and minimize calibration drift. The 2020 also has a signal averaging option to
improve the stability of readings on low turbidity samples.
The 2020 has two different turbidity calibrations, formazin and Japan Standard. The
formazin calibration is the EPA and ISO approved method of calibrating
nephelometers. This calibration can be used with user prepared formazin standards or
commercially purchased formazin standards. LaMotte Company approved AMCO
TM
standards labeled for use with the 2020 can also be used with the formazin
calibration. Stablcal
â
standards below 50 NTU should not be used to calibrate the
2020.
The Japan Standard calibration is a calibration for a Japanese Water Works standard.
It is based on Japanese formulated polystyrene turbidity standards. This calibration
should only be use to meet Japanese Water Works requirements. The Japanese
polystyrene standards can only be purchased in Japan. Formazin, AMCO and
Stablcal
â
standards cannot be used with this calibration.
Taking Turbidity Water Samples
Clean plastic or glass containers may be used for turbidity samples. Ideally, samples
should be tested soon after collection and at the same temperature as when collected.
SAMPLE DILUTION TECHNIQUES
If a test result is out of the range of the meter, it must be diluted. The test should then
be repeated on the diluted sample. The following table gives quick reference
guidelines for dilutions of various proportions.
Amount of Sample Deionized Water to Bring
Final Volume to 10 mL
Multiplication Factor
10 mL 0 mL 1
5mL 5mL 2
2.5 mL 7.5 mL 4
1mL 9mL 10
0.5 mL 9.5 mL 20
INTRODUCTION•SAMPLE DILUTION TECHNIQUES 7
All dilutions are based on a final volume of 10 mL so several dilutions will require
small volumes of the water sample. Graduated pipets should be used for all dilutions.
If volumetric glassware is not available, dilutions can be made with the colorimeter
tube. Fill the tube to the 10 mL line with the sample and then transfer it to another
container. Add 10 mL volumes of deionized water to the container and mix. Transfer
10 mL of the diluted sample to the colorimeter tube and follow the test procedure.
Repeat the dilution and testing procedures until the result falls within the range of the
calibration. Multiply the test result by the dilution factor. For example, if 10 mL of the
sample water is diluted with three 10 mL volumes of deionized water, the dilution
factor is four. The test result of the diluted sample should be multiplied by four.
OPTIONS & SET UP
FACTORY DEFAULT SETTINGS
Settings that have user options have been set at the factory to default settings.
The factory default
settings are:
Turbidity Units NTU
Turbidity Calibration formazin
Averaging Disabled
Date Format MM/DD/YY
Language English
Auto Shutdown Disabled
RESET TO FACTORY DEFAULT SETTINGS
To return the meter to the factory settings, turn the meter off. Hold down *IOK button.
Press ON. Release both buttons. Press *IOK button to select the default settings.
Meter will turn off and the factory settings will be restored. Restoring the factory settings
will remove the user-level calibration but not the zeroing. To change the default
settings follow the instructions in the following sections.
TURBIDITY
The default units are NTU and the default calibration curve is formazin. To change the
settings:
SELECTING TURBIDITY UNITS
1. Press ON to turn the meter on.
1.3
8 OPTIONS & SETUPS • TURBIDITY UNITS
2. Scroll down and then press *IOK
to select Options.
Main Menu
Measure
Data Logging
* Options
16:02:19 01/04/05
3. Scroll down and then press *IOK
to select Turbidity.
Options
Averaging
* Turbidity
Date/Time
Language
16:02:19 01/04/05
4. Press the *IOK to select Units. Turbidity
*Units
Calibration
16:02:19 01/04/05
5. Scroll down and then press *IOK
to select units.
Available units are: NTU
(Nephelometric Turbidity Units);
FNU (Formazin Nephelometric
Units); ASBC (American Society of
Brewing Chemists); EBC (European
Brewery Convention)
Units
NTU
FNU
ASBC
EBC
16:02:19 01/04/05
Note: If Attenuation is chosen as a calibration curve. The result will be reported in
FAU (Formazin Attenuation Units).
6. Press to exit to a previous menu or
make another menu selection or
press OFF to turn the meter off.
OPTIONS & SETUP • TURBIDITY UNITS 9
SELECTING A TURBIDITY CALIBRATION CURVE
1. Press ON to turn the meter on.
1.3
2. Scroll down and then press *IOK to
select Options.
Main Menu
Measure
Data Logging
* Options
16:02:19 01/04/05
3. Scroll down and then press *IOK
to select Turbidity.
Options
Averaging
* Turbidity
Date/Time
Language
16:02:19 01/04/05
4. Scroll down and then press *IOK
to select Calibration.
Turbidity
Units
* Calibration
16:02:19 01/04/05
5. Scroll down and then press *IOK
to select a Calibration curve. Select
a calibration option based on the
composition of the standards that
will be used to calibrate the meter.
Available options are: Formazin,
Japan Standard, Attenuation.
Turbidity
Units
* Calibration
16:02:19 01/04/05
For the most accurate results, the
Attenuation option should be chosen
when samples are over 500 NTU.
The range for the Attenuation option
is 40–4000 NTU.
Calibration
* Formazin
Japan Standard
Attenuation
16:02:19 01/04/05
10 OPTIONS & SETUP • TURBIDITY CALIBRATION
The Japan Standard calibration mode should be used only with Japanese
Polystyrene Standards (0–100 NTU).
Note: StablCal
®
standards below 50 NTU should not be used to calibrate the
2020. The diluent has a different refractive index than traditional formazin
standards and will affect the results.
6. Press to exit to a previous menu or
make another menu selection or
press OFF to turn the meter off.
AVERAGING
The averaging option allows the user to average multiple readings. This option will
improve the accuracy of samples with readings that may tend to drift with time. When
the two, five or ten reading options have been selected, the meter will show a running
average of the readings that have been taken until the final average is displayed. The
default setting is disabled. To change the setting:
1. Press ON to turn the meter on.
1.3
2. Scroll down and then press *IOK
to select Options.
Main Menu
Measure
Data Logging
* Options
16:02:19 01/04/05
3. Press *IOK to select Avera ging. Options
* Averaging
Turbidity
Date/Time
Language
16:02:19 01/04/05
OPTIONS & SETUP • AVERAGING 11
4. Scroll down and then press *IOK to
select an averaging option.
Available options are:
Disabled, 2 Measurements,
5 Measurements,
10 Measurements.
Note: The
*
is displayed next to the
current setting.
Averaging
Disabled
* 2 Measurements
5 Measurements
10 Measurements
16:02:19 01/04/05
5. Press to exit to a previous menu or
make another menu selection or
press OFF to turn the meter off.
Note: When the Averaging option is
selected, it will take longer to get the
final result and more power will be
used.
SETTING THE DATE AND TIME
1. Press ON to turn the meter on.
1.3
2. Scroll down and then press *IOK
to select Options.
Main Menu
Measure
Data Logging
* Options
16:02:19 01/04/05
3. Scroll down and then press *IOK
to select Date/Time.
Options
Averaging
Turbidity
* Date/Time
Language
16:02:19 01/04/05
12 OPTIONS & SETUP • SET DATE & TIME
4. Press *IOK to select Set Date or
scroll down and then press *IOK to
select Set Time or Date Format.
Date/Time
*Set Date
Set Time
Date Format
16:02:19 01/04/05
5. When setting the time or the date,
use the or to change the
highlighted number on the display.
Press *IOK to accept the value and
move to the next value.
Set Date
01/0/4/05
q , * , p
16:02:19 01/04/05
Set Date
01/04/05
q , * , p
16:02:19 01/04/05
Set Date
01/04/05
q , * , p
16:02:19 01/04/05
When choosing a date format, use
the or to select a date format.
Press *IOK to accept format
Date/Time
*Set Date
Set Time
Date Format
16:02:19 01/04/05
6. Press to exit to a previous menu or
make another menu selection or
press OFF to turn the meter off.
OPTIONS & SETUP • SET DATE & TIME 13
SELECTING A LANGUAGE
The default setting is English. To change the setting:
1. Press ON to turn the meter on.
1.3
2. Scroll down and then press *IOK
to select Options.
Main Menu
Measure
Data Logging
* Options
16:02:19 01/04/05
3. Scroll down and then press *IOK
to select Language.
Options
Averaging
Turbidity
Date Time
* Language
16:02:19 01/04/05
4. Scroll down and then press *IOK
to select a language.
Available languages are: English,
French, Spanish, Japanese
(Kana), Portuguese, Italian.
Language
* English
Frances
Español
Japanese
16:02:19 01/04/05
5. Press to exit to a previous menu or
make another menu selection or
press OFF to turn the meter off.
14 OPTIONS & SETUP • SELECTING A LANGUAGE
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