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GAOTek Water Quality Meter with 15 Multiparameter (Advanced)
GAOTek Water Quality Meter with 15 Multiparameter (Advanced)

GAOTek Water Quality Meter with 15 Multiparameter (Advanced)

ID: GT00YY00ZX
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Overview

GAOTek Water Quality Meter with 15 Multiparameter (Advanced) is designed to provide high reliable water quality data by measuring the parameters pH, ORP, Ion, Conductivity, TDS, Salinity, Resistivity and DO of the liquids by immersing its powerful sensor in water. This water meter can be used to examine the quality of a broad range of water samples, from factory effluent to urban drainage, river water, lake and marsh water, aquatic culture tanks, agricultural water supplies, and sea water. It provides laboratory accuracy and ease of push-button operations. It offers built in real time clock stamps stored data and complies with GLP standard.

Key Features

  • Automatic Temperature Compensation provides accurate reading over the entire range
  • Calibration Due Reminder prompts user to calibrate the meter regularly
  • Stability indicator automatically shows current measurement status
  • Auto-Hold function freezes stable measured value for easy viewing and recording
  • Manual temperature calibration corrects temperature deviation
  • Selectable temperature unit (°C or °F) meets different application requirements
  • Automatic electrode diagnosis shows zero point offset and slope of the electrode
  • Help message as an operational guide that helps you quickly begin using the meter
  • System menu allows setting the 15 parameters, including the number of calibration points, resolution, stability condition, measurement unit, etc.
  • Reset feature automatically resumes all parameters back to factory default settings
  • Expanded memory stores and recalls up to 500 readings
  • Built-in real-time clock stamps stored data to meet GLP standard
  • Stored data can be transferred into computer by USB communication interface

Technical Specifications

pH
Range -2.000 pH ~20.000 pH
Accuracy ± 0.002 pH
Resolution 0.1 pH, 0.01 pH, 0.001 pH
Calibration Points 1 to 5 points
Calibration Solutions USA, NIST, DIN, User-Defined Buffer
Temperature Compensation 32 °F~212 °F (0 °C~100 °C), Manual or Automatic
mV
Range -1999.9 mV ~1999.9 mV
Accuracy ± 0.2 mV
Resolution 0.1 mV, 1 mV
Calibration Points 1 point (Only for Relative mV mode)
Calibration Range ± 200 mV
Ion
Range 0.001~19999 ppm, mg/L, mol/L (Depending on range of ISE)
Accuracy ± 0.5 % F.S (Monovalent), ± 1 % F.S (Divalent)
Resolution 0.001, 0.01, 0.1, 1
Calibration Points 2 to 5 points
Calibration Solutions 0.001, 0.01, 0.1, 1, 10, 100, 1000, 10000 ppm, mol/L, mg/L
Conductivity
Range 0~20.00, 200.0, 2000 µS/cm, 20.00, 200.0 mS/cm
Accuracy ± 0.5 % F.S
Calibration Points 1 to 5 points
Calibration Solutions 10 µS/cm, 84 µS/cm,1413 µS/cm,12.88 mS/cm,111.8 mS/cm
Temperature Compensation 32 °F ~ 212 °F (0 °C~100 °C), Manual or Automatic
Temperature Coefficient 0.0 ~ 10.0 %/°C
Compensation Modes Linear or Pure Water
Cell Constant K = 0.1, 1, 10
Normalization Temperature 68 °F or 77 °F (20 °C or 25 °C)
TDS
Range 0~100 ppt (Max. 200 ppt, depending on factor setting)
Accuracy ± 1 % F.S
TDS Factor 0.1~1.0 (Default 0.5)
Salinity
Range 0~10 ppt (Max. 80 ppt)
Accuracy ± 1 % F.S
Measurement Modes Seawater or Practical Salinity
Resistivity
Range 0 MΩ ~100 MΩ
Accuracy ± 1 % F.S
Resolution 0.01, 0.1, 1
Dissolved Oxygen
Range 0.00 mg/L~20.00 mg/L (or ppm)
Accuracy ± 0.2 mg/L
Resolution 0.01 mg/L
Calibration Points 1 or 2 points
Temperature Compensation 32 °F~122°F (0 °C~50°C)
Pressure Correction 60.0 kPa~112.5 kPa, 450 mmHg ~850 mmHg
Salinity Correction 0 g/L~50 g/L
% Saturation of Oxygen
Range 0.0~200.0 %
Accuracy ± 2.0 %
Resolution 0.1 %
Temperature
Range 32 °F~221 °F (0 °C~105 °C)
Accuracy ± 0.9 °F (± 0.5 °C)
Resolution 32.18 °F (0.1 °C)
Calibration Points 1 point, Measured value ± 50 °F (± 10 °C)
Others
Hold Function Manual or Automatic
Stability Conditions Low or High
Calibration Due 0 to 31 days
Power Off Manual or Automatic (10, 20, 30 minutes)
Reset Function Yes
Memory Stores up to 500 data sets
Output USB Communication Interface
Connector BNC
Display LCD
Power Requirements DC 5 V, using AC adapters, 220 V AC/50 Hz
Dimensions (L × W × H) 8.26 in × 7.40 in × 2.36 in (210 mm × 188 mm × 60 mm)
Weight 3.30 lbs (1.5 kg)

Additional Information

Display

This multiparameter water quality meter is equipped with a clear and bright LCD display that shows measured values, mode indicators and help messages.

Keypad

The meter has a succinct membrane keypad, names and symbols describe each function key controls.

     

  • Power the meter ON/OFF.
  • Freezes the measured value on the display, press the key again to resume measuring.
  • In the calibration or temperature setting mode, exits current mode and returns to measurement.

  • Toggles between available measurement modes (pH, mV, ORP, Ion, Conductivity, TDS, Salinity, Resistivity, and DO).
  • Press and hold the key to enter temperature setting mode.

   

  • Press the key to enter the calibration mode.
  • Press and hold the key to enter the setup menu.

 

  • Press the key to store current measured value.
  • Press key in setup mode to scroll up through menu.
  • Press key in temperature setting mode to increase the setting values.

  • Press the key to view calibration report or stored data.
  • Press key in setup mode to scroll down through menu.
  • Press key in temperature setting mode to decrease the setting values.

  • Confirms the calibration, setting value or displayed option.
  • Press and hold the key to turn the backlight On/Off.

Connectors

This multiparameter water quality meter provides 6 connectors for connecting the various types of sensors.

CONNECTOR FUNCTION
pH/ISE For connecting the pH, ORP or Ion Selective Electrodes
ATC For connecting the temperature probe
DO For connecting the dissolved oxygen probe
COND For connecting the conductivity electrode
REF For connecting the reference electrode
USB/ For connecting the USB cable and DC5V power adapter

Connecting the Electrode Holder

The meter comes with an easy-to-use holder for mounting a variety of electrodes and temperature probe. If necessary, please follow the steps below to install the electrode holder.

The base of the electrode holder with an irregular round hole.

 

The electrode arm has a plastic rod.

 

Insert the plastic rod into the irregular round hole and swivel the electrode arm 90°. Electrode holder is now ready to swing into desired position.

 

ADJUSTMENT OF ELECTRODE ARM:

After installation, if the electrode arm automatically rises or falls, you need to adjust the screws until arm locate at any position.

  1. Remove the plastic cover from the electrode arm.

2. Use the screwdriver to tighten the screw moderately.

3. Insert the plastic cover to previous position. Installation is completed.

Connecting the Sensor

Take out the applicable sensors from the packaging. Follow the steps below to place the electrode into left or right sides of the electrode arm.

  

FOR THE pH, ORP OR ION SELECTIVE ELECTRODES:

Insert the BNC connector into the corresponding connector socket. Rotate and push the connector clockwise until it locks. After connection is completed, DO NOT pull on the sensor cord. Always make sure that the connector is clean and dry.

  

FOR THE CONDUCTIVITY ELECTRODE OR DISSOLVED OXYGEN PROBE:

Insert the 6-pin connector into corresponding connector socket, ensure the connector is fully seated.

 Preparing the pH Buffer Solutions

This multiparameter water quality meter is packaged with three pH buffer packets required for calibration.

  • Open the pH 7.00 buffer packet, place the powder into 250 ml volumetric flask. Pour distilled water 250 ml to scale line, mix the solution until reagent is completely dissolved.
  • Preparation of pH 4.01 and 10.01 standard buffer solutions are the same as above.
  • Prepared standard buffer solutions should be stored in hermetically sealed glass containers. 

Refilling Electrolyte Solution for DO Probe

  1. Unscrew the membrane cap from the bottom of the dissolved oxygen probe.

  1. Fill the membrane cap halfway with electrolyte solution.

  1. Screw the membrane cap onto the probe, excess electrolyte will drain out.

  1. Be sure the cathode of probe makes contact with membrane cap, the electrolyte solution in membrane cap should be without an air bubble.

                 

 Prior to Use

Remove the protective cap from the bottom of the sensor.

  • FOR THE pH ELECTRODE:

If the glass sensitive membrane on the electrode dries out, soak the electrode in 3 M KCl solution or tap water for at least 15 minutes. DO NOT use distilled or deionized water, it will shorten the life of sensor.

  • FOR THE ORP ELECTRODE:

Soak the electrode in 3 M KCl solution or tap water for 5 minutes.

  • FOR THE ION SELECTIVE ELECTRODES:

Soak the electrode in the diluted standard solution (e.g., 100 ppm) for at least 15 minutes.

  • FOR THE CONDUCTIVITY ELECTRODE:

Soak the electrode for a few minutes in tap water to remove dirt and oil stains on the electrode.

  • FOR THE DISSOLVED OXYGEN PROBE:

Connecting the probe to meter, turn on the meter 10 to 15 minutes and wait for the probe to polarize.

 Power On/Off

  • Press MEAS key to turn on the meter, the display shows measured values, mode indicators and help messages.
  • Press and hold the MEAS key for 3 seconds, the meter will turn off.
  • If you do not press any key within the specified time period, the meter will turn off automatically.

 

To disable the auto-off function, please read the SETUP MENU section.

 Setup Menu

This multiparameter water quality meter contains an integrated setup menu that allows you to customize each displayed option to meet measurement requirements. In the different modes, the meter will show the corresponding options. For the general options, once it is changed that will be applied to all modes.

pH MODE:

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
      pH Buffers:

Select your desired pH buffer group for calibration and auto-recognition.

      USA (1.68, 4.01, 7.00, 10.01, 12.45)
NIST (1.68, 4.01, 6.96, 9.18, 12.45)
      DIN (1.09, 4.65, 6.79, 9.23, 12.75)
User-Defined Buffer
      Calibration Points:

Select the number of calibration points you intend to calibrate the meter.

           1 1 point
          2 2 points
         3 3 points
          4 4 points
          5 5 points
Resolution:

Sets the resolution for pH measurement.

0.001 0.001 pH
 0.01 0.01 pH
0.1 0.1 pH
Measurement Unit:

Sets the default temperature unit.

   Degrees Celsius
   Degrees Fahrenheit

ORP MODE:

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
  Resolution:

Sets the resolution for ORP measurement.

        0.1 0.1 mV
         1 1 mV

ION MODE:

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
Measurement Unit:

Sets the default ion concentration and temperature units.

ppm Parts per million
mg/L Milligrams per liter
mol/L Moles per liter
           Degrees Celsius
           Degrees Fahrenheit
  Calibration Points:

Select the number of calibration points.

        2 2 points
      3 3 points
         4 4 points
          5 5 points
       Ion Valence:

Select the ion valence of sensor.

    1 Monovalent
  2 Divalent

CONDUCTIVITY/TDS/SALINITY/RESISTIVITY MODES:

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
  Cell Constant:

Select the cell constant of conductivity electrode.

    0.1 K=0.1
   1 K=1
        10 K=10
User-Defined
        Temperature Coefficient:

Select the temperature coefficient of sample.

   2.10 Setting Range: 0.0 to 10.0%/°C 2.10
      Calibration Points:

Select the number of calibration points.

       1 1 point
     2 2 points
       3 3 points
       4 4 points
      5 5 points
Pure Water Coefficient:

Pure water coefficient will be calculated and applied automatically for ultra-pure water measurement if enabled.

     YES Enable
     NO Disable
    Normalization Temperature:

Sets the normalization temperature for conductivity measurement and calibration.

      25 °C
    20 °C
      TDS Factor:

Sets the default TDS conversion factor.

      0.5 Setting Range: 0.40 to 1.00 0.5
   Measurement Unit:

Sets the default temperature unit.

     Degrees Celsius
     Degrees Fahrenheit

DISSOLVED OXYGEN MODE: 

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
      Calibration Points:

Select the number of calibration points.

      1 1 point
      2 2 points
Pressure Coefficient:

Select the default atmospheric pressure coefficient.

     760 Setting Range: 450 mmHg to 850 mmHg 760
      Salinity Coefficient:

Select the salinity coefficient of sample solution.

        0.0 Setting Range: 0.0 ppt to 50.0 ppt 0.0
Resolution:

Sets the resolution for DO measurement.

    0.01 0.01 mg/L (0.1 %)
    0.1 0.1 mg/L (1 %)
Measurement Unit:

Sets the default measurement units.

        Degrees Celsius
        Degrees Fahrenheit
mg/L Milligrams per liter
ppm Parts per million
mmHg Pressure unit
kPa Pressure unit

GENERAL OPTIONS:

PARAMETER DESCRIPTION OPTIONS DESCRIPTION DEFAULT
    Stable Criteria:

Sets the stability criteria for measurement.

When the “LO” option is enabled, measuring value will stabilize quickly, but reading is less accurate.  When the “HI” option is enabled, measuring value will stabilize slowly, but guarantees high accuracy.

 LO Low
 HI High
Auto-Hold:

When the auto-hold function is enabled, the meter will automatically sense a stable end-point reading and freeze it.

  YES Enable
  NO Disable
OFF Auto-Power Off:

When the auto-off power is enabled, if you do not press any key within a specified time period, the meter will automatically turn off.

 10 10 minutes
 20 20 minutes
30 30 minutes
NO Disable
CALL Calibration Due:

When calibration due reminder is enabled, if you do not recalibrate meter within a specified time period, the meter will automatically show  indicator.

1 … 31 1 to 31 days
 OFF Disable
Date and Time:

Sets the date and time of the meter.

      Clear stored data:

Clear all stored data.

YES Enable
NO Disable
      Reset:

Reset function allows user to restore the meter back to factory default parameters. When this function is enabled, all calibration values and selected parameters will be lost or reset.

YES Enable
NO Disable

SETTING THE DEFAULT PARAMETERS:

  1. If necessary, press MODE key until the display shows corresponding mode indicator (e.g., pH mode).

  1. Press and hold the key for 3 seconds, the meter enters setup menu, the display shows selectable parameter and page number.

  1. Press  orkey to scroll through menu, select the parameter you want to set.

  1. Press ENTER key to confirm, the display shows an option in the submenu.

  1. Press  orkey to select the desired option.
  2. Press ENTER key to confirm, the meter returns to measurement mode. Setting is completed.

EXIT THE SETUP MENU:

During the setup mode, if you want to exit setup menu, press MEAS key, the meter will return to measurement mode immediately.

Temperature Compensation

In order to get accurate measuring results, you need to enable the manual or automatic temperature compensation before measurement or calibration.

AUTOMATIC TEMPERATURE COMPENSATION:

  • Place the temperature probe into the circular hole of electrode arm.

  • Insert the connector of temperature probe into corresponding connector socket (Marked “ATC”).

  • The “ATC” indicator will be shown on the display; the meter is now switched to automatic temperature compensation mode.

 

MANUAL TEMPERATURE COMPENSATION:

  1. DO NOT connect the temperature probe to meter.
  2. Press and hold the °C key for 3 seconds to enter temperature setting mode.
  3. Press  orkey to set the temperature value of sample.
  4. Press ENTER key to confirm, the meter returns to measurement mode. Setting is completed.

In the temperature setting mode, press  orkey once, the setting value will increase or decrease by 0.1. Press and hold the  orkey, the setting value will increase or decrease by 1.

In the dissolved oxygen mode, DO NOT connect the temperature probe to meter. The dissolved oxygen probe has a built-in temperature sensor.

pH Calibration

This multiparameter water quality meter allows up to 5 points calibration in the pH mode. It is recommended that you perform at least 2 points calibration for high accuracy measurement. The meter will automatically recognize and calibrate to following standard buffer values.

USA Standard Buffer Options pH 1.68, 4.01, 7.00, 10.01, 12.45
NIST Standard Buffer Options pH 1.68, 4.01, 6.86, 9.18, 12.45
DIN Standard Buffer Options pH 1.09, 4.65, 6.79, 9.23, 12.75

If you selected the user-defined option in the setup menu, the meter will allow only 2 points calibration. Single point calibration should only be carried out with pH 7.00, 6.86 or 6.79, otherwise calibration will not be accepted.

Make sure to calibrate the meter when attaching a new electrode or during first use. DO NOT reuse calibration solution after calibration, contaminants in solution will affect the calibration and eventually the accuracy of the measurement.

SINGLE POINT CALIBRATION:

  • Make sure that you have selected 1 point calibration in the setup menu.
  • Rinse the pH electrode with distilled water.
  • Press CAL key, the meter shows “pH7.00/CAL” (or “6.86/CAL”, “6.79/CAL”).

  • Dip the pH electrode into the pH7.00 (or 6.86, or 6.79) buffer solution, the end of the electrode must be completely immersed into the calibration solution. Stir the sensor gently to create a homogenous solution.
  • Press ENTER key, “Calibration” indicator begins flashing. Wait for the measured value to stabilize, the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

MULTI-POINT CALIBRATION:

  • Make sure that you have selected 2 to 5 points calibration in the setup menu.
  • Repeat above steps. When the first calibration point is completed, the display will show “CAL2”. The meter prompts you to continue with second point calibration.

  • Rinse the pH electrode with distilled water. Dip the electrode into the next standard buffer solution (e.g., pH4.01). The meter automatically senses the current calibration solution and begins calibrating. “Calibration” indicator begins flashing.

  • Wait for the measured value to stabilize, the display shows “CAL3”. The meter prompts you to continue with third point calibration.
  • Repeat the steps until the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

  

pH Calibration Report

This program lets you check the parameters of pH electrode for diagnostic purposes.

  1. Press MR key in the pH measurement mode, the display shows “LOC/P-01”.
  2. Press  orkey until the meter shows “ELE/P-02” (Electrode Diagnosis).

  1. Press ENTER key to confirm, the meter shows the last calibration date (Format: mm-dd).

  

  1. Press key, the meter shows “OFS” (zero-point offset potential).

5. Press key again, the meter shows the slope of each pH buffer group.

 

  1. After the browsing, press MEAS key to exit the current mode.

If you did not calibrate the meter or calibration is not successful, press MR key, the display will show “—-” only.

ORP Calibration

This multiparameter water quality meter allows 1 point calibration in the relative mV mode, but calibration is not necessary unless exact readout agreement with a work standard and at a specific ORP value is needed.

  1. Press MODE key until the meter shows   indicator.

  1. Rinse the ORP electrode with distilled water. Dip the electrode into the calibration solution. Stir the sensor gently.
  2. Press CAL key, the meter shows the current measured value.

  1. Press  orkey to set the displayed value, press ENTER key to confirm. “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display shows “END”. The meter returns measurement mode automatically. Calibration is completed.

 ORP Calibration Report

This program lets you check the millivolt offset in the ORP mode.

  1. Press MR Key in the ORP measurement mode, the display shows “LOC/P-01”.
  2. Press  orkey until the meter shows “ELE/P-02” (Electrode Diagnosis).

  1. Press ENTER key to confirm, the meter shows the last calibration date (Format: mm-dd).

  1. Press key, the meter shows “OFS” (Offset Potential).

  1. After the browsing, press MEAS key, the meter returns to measurement mode.

 Ion Concentration Calibration

This multiparameter water quality meter supports ion concentration calibration up to 5 points with minimum of 2 points, available calibration points include the following options.

MEASUREMENT UNITS CALIBRATION POINTS
ppm 0.001, 0.01, 0.1, 1, 10, 100, 1000, 10000
mg/L 0.001, 0.01, 0.1, 1, 10, 100, 1000, 10000
mol/L 0.001, 0.01, 0.1, 1, 10
mmol/L 0.001, 0.01, 0.1

To obtain accurate measurement results, it is recommended that you perform ion calibration and measurement at same temperature. If you did not calibrate the meter or calibration is not successful, the display will always show “0.000”.

  1. Press MODE key until the meter shows  indicator.

  1. If necessary, select the concentration unit and ion valence (Monovalent or Divalent) in the setup menu (Refer to Setup Menu section).

NOTE: The meter is capable of using the mg/L, ppm or mol/L as measurement unit of concentration. The factory default is ppm. If you had converted concentration unit, the display will show “CAL” and will flash uninterruptedly. When CAL key is pressed the meter enters the calibration mode.

  1. Press CAL key, the meter shows 0.001 ppm (or mg/L, mol/L, mol/L).

  1. If necessary, press  orkey to select the desired calibration point (e.g., 0.01 ppm).

  1. Rinse the Ion Selective Electrode with distilled water, then rinse with a small amount of ion standard solution.
  2. Dip the electrode into corresponding calibration solution. Stir the sensor gently to create a homogenous solution.
  3. Press ENTER key to confirm, “Calibration” indicator begins flashing. Wait for the measured value to stabilize, the display shows “0.1/CAL2”. The meter prompts you to continue with second point calibration.

  1. Rinse the Ion Selective Electrode with distilled water. Dip the electrode into corresponding calibration solution. Stir the sensor gently.
  2. Press ENTER key, “Calibration” indicator begins flashing. Wait for the measured value to stabilize, the display shows “1/CAL3”. The meter prompts you to continue with third point calibration.

  1. Repeat steps 8 to 9 above until the display shows “END”, the meter returns to measurement mode automatically. Calibration is completed.

EXIT THE CALIBRATION:

During the calibration process, if you want to exit calibration, press MEAS key, the meter will return to measurement mode immediately.

Ion Calibration Report

This program lets you check the slope of the Ion Selective Electrode.

  1. Press MR Key in the ion measurement mode, the meter shows “LOC/P-01”.
  2. Press  orkey until the display shows “ELE/P-02” (Electrode Diagnosis).

  1. Press ENTER key to confirm, the meter shows the last calibration date (Format: mm-dd).

   

  1. Press key, the meter shows calibration point and its slope.

  1. After the browsing, press MEAS key to exit the current mode.

Conductivity Calibration

This multiparameter water quality meter is capable of using the three types of conductivity electrodes. Before calibration or measurement, you need to select the different sensors as per your sample concentration. The table below shows available sensors and its effective measuring ranges.

CONDUCTIVITY ELECTRODE MEASURING RANGES CELL CONSTANT
CON-0.1 0.1 µS/cm~100 µS/cm K = 0.1
CON-1 0.01 mS/cm ~10 mS/cm K = 1
CON-10 0.1 mS/cm ~200 mS/cm K = 10

Make sure that you selected the cell constant between 0.1, 1 or 10 in the setup menu. If the current option is “USER”, the automatic calibration function will be disabled.

In the automatic calibration mode, the meter allows up to 5 points calibration. To ensure higher accuracy, it is recommended that you perform 3 points calibration or select a standard value close to the sample value you are measuring. The meter will automatically detect these conductivity standard solutions and prompt the user to calibrate the meter. When the calibration is completed, all new calibration values will automatically override existing data.

The following table shows acceptable conductivity range of calibration solution for each measuring range.

MEASURING RANGE CALIBRATION SOLUTION RANGE DEFAULT
0 µS/cm ~20 µS/cm 7 µS/cm ~17 µS/cm 10 µS/cm
20 µS/cm ~200 µS/cm 70 µS/cm ~170 µS/cm 84 µS/cm
200 µS/cm ~2000 µS/cm 700 µS/cm ~1700 µS/cm 1413 µS/cm
2 mS/cm ~20 mS/cm 7 mS/cm ~17 mS/cm 12.88 mS/cm
20 mS/cm ~200 mS/cm 70 mS/cm ~170 mS/cm 111.8 mS/cm

SINGLE POINT CALIBRATION:

  1. Press MODE key until the meter shows   indicator.

  1. Rinse the conductivity electrode with distilled water, then rinse with a small amount of calibration solution.
  2. Press CAL key, the meter enters the calibration mode.
  3. Dip the conductivity electrode into the calibration solution, the meter automatically shows current calibration standard (e.g., 1413 µS/cm).

  1. Press ENTER key to confirm, “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

 MULTI-POINT CALIBRATION:

  1. Make sure that you have selected 2 to 5 points calibration in setup menu.
  2. Repeat steps 2 to above, when the first calibration point is completed, the display will show “CAL2”. The meter prompts you to continue with second point calibration.

  1. Rinse the conductivity electrode with distilled water. Dip the electrode into the next calibration solution, the meter automatically shows current calibration standard (e.g., 12.88 mS/cm).
  2. Press ENTER key to confirm, “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display shows “CAL3”. The meter prompts you to continue with third point calibration.
  2. Repeat steps 3 to 4 above until the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

MANUAL CALIBRATION:

This meter provides a quick manual calibration mode that allows user to easily calibrate the meter.

  1. Record the cell constant value on the electrode (e.g., K = 1.08).

  1. Press and hold the key for 3 seconds to enter setup menu, the display shows “CELL” option.

  1. Press ENTER key to confirm, the meter enters the cell constant setting mode.

  1. Press  orkey to select “USER” option.

  1. Press ENTER key to confirm, the meter enters User-Defined mode.

  1. Press  orkey to set each digit according to previous record.
  2. Press ENTER key to confirm until the setting values stop flashing. The meter returns to measurement mode automatically. Setting is completed.

  • During the calibration process, if you want to exit calibration, press MEAS key, the meter will return to measurement mode immediately.
  • Performing the conductivity calibration will simultaneously calibrate the corresponding TDS, salinity and resistivity value.

Conductivity Calibration Report

This program lets you check the calibration factor of the conductivity electrode.

  1. Press MR key in the conductivity measurement mode, the display shows “LOC/P-01”.
  2. Press  orkey until the meter shows “ELE/P-02” (Electrode Diagnosis).

  1. Press ENTER key to confirm, the meter shows the last calibration date (Format: mm-dd).

  1. Press key, the meter shows calibration point and calibration factor (e.g., K = 0.998).

  1. After the browsing, press MEAS key to exit the current mode.

DO Calibration in % Saturation Mode

This multiparameter water quality meter can be calibrated quickly in air. In the percentage saturation mode, the meter is able to perform either 1 or 2 points calibration. For single point calibration, it is recommended that you perform 100% saturation calibration in the air. For the 2 points calibration, you need to use saturated anhydrous sodium sulfite solution (zero oxygen solution).

100% SATURATION CALIBRATION:

  1. Press MODE key until the meter shows indicator.

  1. Make sure that you have selected 1 point calibration in the setup menu.
  2. Press CAL key, the meter enters calibration mode, the display shows “100%/CAL1”.

  1. Hold the dissolved oxygen probe in the air, press ENTER key to confirm. Wait for the measured value to stabilize, the display shows “END”. Single point calibration is completed.

2 POINTS CALIBRATION:

  1. Make sure that you have selected 2 points calibration in the setup menu.
  2. Press CAL key, the meter shows “100/CAL1”.
  3. Press  orkey until the display shows “0/CAL1”.

  1. Dip the dissolved oxygen probe into the saturated anhydrous sodium sulfite solution (zero oxygen solution). Stir the probe gently.
  2. Press ENTER key to confirm, “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display shows “100/CAL2”. The meter prompts you to continue with second point calibration.

  1. Dip the dissolved oxygen probe into air-saturated water for 3 to 5 minutes, press ENTER key to confirm. Wait for the measured value to stabilize, the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

Performing a percentage saturation calibration will simultaneously calibrate the corresponding mg/L (or ppm) concentration value. Therefore, additional mg/L calibration isn’t required in most circumstances.

DO Calibration in mg/L or ppm Mode

  1. Press MODE key until the meter shows indicator and measurement unit “mg/L” or “ppm”.

  1. Make sure that you have selected 1 point calibration in the setup menu.
  2. If necessary, set the salinity and atmospheric pressure coefficient in the setup menu.
  3. Press CAL key, the display shows “8.25 mg/L/CAL1” (@25 °C).

  1. Dip the dissolved oxygen probe into the air-saturated water for 3 to 5 minutes.
  2. Press ENTER key to confirm, “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display will show “END”. The meter returns to measurement mode automatically. Single point calibration is completed.

2 POINTS CALIBRATION:

  1. Make sure that you have selected 2 points calibration in the setup menu.
  2. Press CAL key, the meter shows “8.25 mg/L/CAL1” (@25 °C).
  3. Press  orkey until the display shows “0.00 mg/L/CAL1”.

  1. Dip the dissolved oxygen probe into the saturated anhydrous sodium sulfite solution (zero oxygen solution). Stir the probe gently.
  2. Press ENTER key to confirm, “Calibration” indicator begins flashing.

  1. Wait for the measured value to stabilize, the display shows “8.25/CAL2”. The meter prompts you to continue with second point calibration.

  1. Dip the dissolved oxygen probe into air-saturated water for 3 to 5 minutes, press ENTER key to confirm. Wait for the measured value to stabilize, the display shows “END”. The meter returns to measurement mode automatically. Calibration is completed.

EXIT THE CALIBRATION:

During the calibration process, if you want to exit calibration, press MEAS key, the meter will return to measurement mode immediately.

Temperature Calibration

During the measurement, when automatic temperature compensation is enabled, if the temperature reading displayed differs from that of an accurate thermometer, you need to calibrate the meter.

  1. Press and hold the °C key for 3 seconds to enter temperature calibration mode, the display shows current temperature reading.

2. Press  orkey to set the temperature value.

3. Press ENTER key to confirm. Calibration is completed.

 pH Measurement

  1. Press MODE key until the meter shows indicator.
  2. Rinse the pH electrode with distilled water to remove any impurities adhering to the probe body.
  3. Dip the electrode into the sample solution, stir the sensor gently.
  4. Wait for the reading to stabilize, record the measured value on the display.

ORP Measurement

This multiparameter water quality meter contains two millivolt measurement modes.

ABSOLUTE MILLIVOLT MODE:

Press MODE key until the display shows indicator, the meter enters relative millivolt measurement mode.

Select one of the above modes. Dip the ORP electrode into sample solution, stir the sensor gently. Wait for reading to stabilize, record the measured value on the display.

Ion Concentration Measurement

  1. Press MODE key until the meter showsindicator.
  2. Rinse the Ion Selective Electrode thoroughly with distilled water. Dip the electrode into the sample solution.
  3. If your sample belongs to low concentration liquids or some interfering ions are present in the solution, it is suggested that you add the Ionic Strength Adjuster into the sample solution.
  4. Stir the sensor gently. Wait for the reading to stabilize, record the measured value on the display.

Conductivity/TDS/Resistivity Measurement

  1. Press MODE key until the meter shows (conductivity) or  (TDS) or  (Resistivity) indicator.

  1. Rinse the conductivity electrode thoroughly with distilled water.
  2. Dip the electrode into the sample solution, stir the sensor gently.
  3. Wait for the reading to stabilize, record the measured value on the display.

Salinity Measurement

This meter provides two salinity measurement modes: practical salinity (unit: PSU) and natural seawater (unit: ppt).

  1. Press MODE key until display shows indicator and measurement unit “PSU”, the meter now enters practical salinity measurement mode.

2. If necessary, press MODE key again, the meter shows indicator and mesurement unit “ppt”, the meter now enters seawater measurement mode.

3. Select the desired measurement mode. Dip the electrode into sample solution. Stir the sensor gently.

4. Wait for the reading to stabilize, record the measured value on the display.

Dissolved Oxygen Measurement

This multiparameter water quality meter is suitable for measuring the water, wastewater, brine and other liquids. If you use meter to measure seawater or other water containing large amounts of salt, please set the salinity coefficient before use.

Some gas and steam such as chloride, sulfur dioxide, sulfureted hydrogen, ammonium, carbon dioxide and iodin can permeate the membrane via diffusion. So their existence will influence the measurement of dissolved oxygen.

If the sample contains solvent, grease, sulfide and alga, the membrane on the probe will be blocked, damaged or eroded.

  1. Press MODE key until the meter showsindicator.
  2. Connecting the dissolved oxygen probe to meter, wait for 15 minutes to polarize the sensor.
  3. If necessary, to set the atmospheric pressure and salinity coefficient in the setup menu (Refer to “SETUP MENU” section).
  4. Submerse probe in the sample solution, make sure the temperature sensor on the probe is fully immersed.

  1. Stir the probe gently, wait for the reading to stabilize, record the measured value on the display.

 Hold Function

The meter contains two data hold modes

 Storing and Recalling Data from Memory

This multiparameter water quality meter allows up to 500 data sets to be stored and recalled.

Communication Software

This instrument comes with a free Data Acquisition System that can be used to transfer stored data, receive the measuring values or set the interval time for automatic recording. The system requirement is Windows XP or Windows 7.

NOTE:

  • The software is run in operating system Windows XP. If your system is Windows 7, please using the file “CP210x_VCP_Windows” to update your device manager.
  • If the computer displays “Error” during the first run, please open the windows “Run” command, then enter the command below in text input field:

regsvr32 “c:\windows\system32\DAO350.DLL

  • Please make sure your meter is connected to communication port “COM1”, baud rate: 9600.

 pH Electrode Care and Maintenance

Since pH electrode is susceptible to dirt and contamination, clean as necessary depending on the extent and condition of use.

AFTER MEASURING: 

Rinse the pH electrode in distilled water, store the electrode into the electrode storage solution.

CLEANING THE ELECTRODE:

  • Salt deposits: Soak the electrode in warm tap water to dissolve deposits, then thoroughly rinse with distilled water.
  • Oil or Grease film: Wash the electrode bulb gently in some detergents and water. If necessary, using the alcohol to clean the electrode bulb, then rinse with distilled water. Place the sensor in the electrode storage solution for 30 minutes.
  • Clogged reference junction: Heat a diluted KCl solution to 140 °F to 176 °F (60 °C to 80 °C). Place the sensing part of the electrode into the heated solution for about 10 minutes. Allow the electrode to cool in some unheated KCl solution.
  • Protein deposits: Prepare a 1% pepsin solution in 0.1 M of HCL. Place the electrode in the solution for 10 minutes. Rinse the sensor with distilled water.

REACTIVATING THE ELECTRODE:

If stored and cleaned properly, the electrode should be ready for immediate use. However, a dehydrated bulb may cause sluggish response. To rehydrate the bulb, immerse the electrode in a pH 4.01 buffer solution for 10 to 30 minutes. If this fails, the electrode requires activation.

  • Soak the pH electrode in 0.1 M HCl for 5 minutes.
  • Remove and rinse with deionized water, then place in 0.1 M NaOH for 5 minutes.
  • Remove and rinse again, and soak in electrode storage solution for 30 minutes.

ORP Electrode Care and Maintenance

  • Ensure that the ORP electrode is thoroughly washed with distilled water after each use.
  • In aggressive chemicals, dirty or viscous solutions, and solutions with heavy metals or proteins, take readings quickly and rinse electrode immediately after.
  • If you do not use the electrode for long periods, please store the electrode with electrode storage solution.

CLEANING THE ELECTRODE:

Contamination of the sensing element often results in slow response and inaccurate readings. If necessary, clean the element by one of the following procedures.

Inorganic Deposits: 

  • Soak the ORP electrode in 0.1M HCl for 10 minutes.
  • Remove and rinse with distilled water, then place in alcohol for 5 minutes.
  • Remove and rinse again, and soak in pH4.01 buffer solution for 15 minutes.

Oil and Grease Films: 

  • Wash the electrode gently in some detergents and water.
  • Dip the electrode in the electrode storage solution for at least 30 minutes.

 Ion Selective Electrode Care and Maintenance

  • Ensure that the electrode is thoroughly washed with distilled water after each use.
  • DO NOT scratch the sensitive membrane on electrode during the measurement or calibration.
  • If you do not use the electrode for long periods, please store the electrode in a dry, cool and well-ventilated area.

Conductivity Electrode Care and Maintenance

  • Ensure that the conductivity electrode is thoroughly washed with distilled water after each use.
  • If there is a build-up of solids inside the measurement area of the cell, these should be removed very carefully with a cotton bud soaked in solvent, taking care not to touch the metal parts of the inner cell.

DO Probe Care and Maintenance

  • Please always keep probe’s membrane moist.
  • If you do not use the dissolved oxygen probe for long periods, please screw off membrane cap and rinse the probe’s cathode, anode and the membrane with deionized water, then soak up residual water on them with filter paper, and install the probe.

    

Troubleshooting

LCD DISPLAY CAUSE CORRECTIVE ACTION
Electrode dried out Soak the pH electrode in 3M KCL solution for 15 minutes
Soak the Ion Selective Electrode in the diluted standard solution
Soak the conductivity electrode in tap water for a few minutes
Measured value is out of range Check the electrode whether clogged, dirty or broken
Incorrect calibration solutions Using the fresh calibration solutions for calibration
Setting value does not match calibration solution Reset the calibration value
DO electrolyte solution is depleted Refilling electrolyte solution
Zero oxygen solution is contaminated Replace the calibration solution
pH electrode is out of service life Replace the pH electrode

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