QED MicroPurge MP25 User manual

Operation Manual
MicroPurge® Flow Cell
MP25 & MP2T
QED Environmental Systems Inc.
2355 Bishop Circle West
Dexter, MI 48103
A Graco Company

Rev: 01 P/N: 95343 Page | 1
Safety Warnings
Wear appropriate Personal Protective Equipment (PPE) including safety glasses when working with the
QED MP25 or MP25T.
Intended for use with groundwater wells and common sampling pump systems with flow control
capability.
Table of Contents
1. Introduction........................................................................................................................................................3
1.1 Components ...............................................................................................................................................3
2. MP25 and MP25T Sonde ....................................................................................................................................4
2.1 MP25 and MP25T Sensor/Parameter List ........................................................................................................4
2.2 MP25 Sensors ...................................................................................................................................................4
2.3 MP25T Sensors .................................................................................................................................................5
2.4 MP25 and MP25T Flow Cell Setup ...................................................................................................................5
2.5 LED Indicators...................................................................................................................................................7
2.6 Cleaning and Storage........................................................................................................................................8
3. MicroPurge®Application Software ...................................................................................................................8
3.1 Installing the MicroPurge® App........................................................................................................................8
MicroPurge Application
tinyurl.com/ycal8zyq
MP25 & MP25T Manual
tinyurl.com/yawc4kb7
MP25 & MP25T Quick
Calibration Guide
tinyurl.com/y8lfh8j8

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3.2 Connecting your MP25 or MP25T for the first time.........................................................................................8
3.3 Home Screen ....................................................................................................................................................9
3.3.1 Snapshot ....................................................................................................................................................9
3.3.2 Find Another MP25 ................................................................................................................................ 10
3.3.3 View PurgeScan Logs .............................................................................................................................. 10
3.3.4 Settings ................................................................................................................................................... 10
3.4 Calibration and Calibration Logs.................................................................................................................... 10
3.4.1 Calibration .............................................................................................................................................. 10
3.4.2 Calibration Logs ...................................................................................................................................... 19
3.5 PurgeScan® Logging and Setup ..................................................................................................................... 20
3.5.1 PurgeScan Logging Setup and Interval ................................................................................................... 20
3.5.2 PurgeScan Logs....................................................................................................................................... 20
3.5.3 Sensors and Parameters......................................................................................................................... 20
3.5.4 Configure Stabilization Criteria............................................................................................................... 21
3.6 Backup Logs ................................................................................................................................................... 22
3.7 Other Operations........................................................................................................................................... 23
3.7.1Tablet Scroll Interval................................................................................................................................ 23
3.7.2 Bluetooth Scan Filter .............................................................................................................................. 23
3.7.3 Save GPS Location .................................................................................................................................. 23
3.7.4 Software Version .................................................................................................................................... 23
3.7.5 Wipe Turbidity Sensor ............................................................................................................................ 24
3.7.6 Selecting a storage location for PurgeScan Log Files ............................................................................. 25
4. Technical Notes ................................................................................................................................................... 25
4.1 Dissolved Oxygen........................................................................................................................................... 25
4.1.1 Oxygen Solubility in Water ..................................................................................................................... 25
4.1.2 Salinity Correction of DO mg/L............................................................................................................... 25
4.1.3 Barometric Pressure of Functions .......................................................................................................... 25
4.2 Specific Conductance, Salinity, and TDS........................................................................................................ 26
4.2.1 Specific Conductance Temperature Correction ..................................................................................... 26
4.2.2 Salinity Calculation ................................................................................................................................. 26
4.2.3 Total Disolved Salts (TDS) Calculation .................................................................................................... 26
4.3 CE Testing and Certification........................................................................................................................... 26

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4.4 Turbidity ........................................................................................................................................................ 26
5. Troubleshooting .................................................................................................................................................. 26
6. Warranty.............................................................................................................................................................. 27
1. Introduction
1.1 Components
1. MP25 or MP25T Multi-parameter Sonde with Storage/Calibration Cup
2. Bluetooth Battery Module
3. 3 meter waterproof cable
4. Bluetooth Battery Charger
1
.
2
8
4
3
6
.
5
7
9
10
11

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5. Calibration Stand
6. Flow Cup
7. Maintenance Kit
8. Sensor Guard
9. PTFE Thread Tape 1/4”
10. MP25 Flow Cell Adaptor
11. Assorted Fittings for flow cell connections to sampling pump tubing
2. MP25 and MP25T Sonde
2.1 MP25 and MP25T Sensor/Parameter List
1. Temperature (°C)
2. Temperature (°F)
3. pH (units)
4. pH (mV)
5. Specific Conductivity (µS/cm)
6. Specific Conductivity (mS/cm)
7. ORP (mV)
8. TDS (mg/L)
9. HDO (%Sat)
10. HDO (mg/L)
11. Salinity (PSS)
12. Turbidity (NTU) [MP25T Only]
2.2 MP25 Sensors
Conductivity
Temperature
pH/ORP Reference
Electrode
pH /ORP
Dissolved Oxygen

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2.3 MP25T Sensors
2.4 MP25 and MP25T Flow Cell Setup
2.4.1 Steps to connect the Flow Cell to the MP25 or MP25T
1. Remove storage cup from sonde
2. Attach flow cell adaptor to end of sonde (Only needed for MP25, MP25T has integral bayonet pins on
the sonde bottom cap.)
3. Insert sonde/adaptor into flow cell and push into bayonets slots, then turn sonde clockwise to lock.
Turbidity
Temperature
pH/ORP Reference
Electrode
Dissolved Oxygen
Conductivity
pH /ORP

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4. Determine necessary flow cell inlet connection fittings based on pump discharge tubing type and size.
5. Connect the included flow cell flexible tubing from pump to flow cell and then from flow cell discharge
to purge water collection bucket.
NOTE: The flow cell is designed to be used in either a horizontal or vertical position. Any gas bubbles in
the flow stream are vented out of the cell and away from the sensors weather vertical or horizontal. The
flow cell and sonde setup can be used while resting in the case as shown in the photo below as a
convenient work platform or will stand or rest on any flat surface. Horizontal use is preferred to avoid
possible damage if the standing sonde were to fall over.

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2.5 LED Indicators
Both the MP25 and MP25T have three LED indicators mounted to the internal circuit board, to provide
troubleshooting information to the user. The LEDs can be seen through the gap in the label, in the same window
as the serial number when the sonde is connected to the application.
Green LED: Blinks every one second to indicate adequate voltage from the Bluetooth Battery Pack.
Amber LED: Blinks once when the system is receiving RS-232 communication and blinks twice when the
PurgeScan Logging is activated.

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Red LED: Blinks five times at power-up when logging is enabled.
2.6 Cleaning and Storage
Clean your instrument periodically with warm soapy water. Clean sensor stems
with a soft brush. Laboratory-grade liquid detergent is preferred, but liquid
dishwashing soap is fine. Do not use abrasives. Do not use solvents such acetone.
Do not clean with gasoline, kerosene, or industrial cleaners. Rinse sensors free of
soap with tap water and store the sensors in tap water (see below).
Replace any o-rings with visible cracks. Keep o-rings greased with silicon grease
(found in your Maintenance Kit).
When storing the MP25 or MP25T, fill the storage cup provided with 1-2 oz. of tap or bottled drinking water and
install the storage cup on the sonde. NOTE: DO NOT use purified water such as, distilled, deionized or reverse
osmosis water for storage, as this will deplete the pH sensor and reference electrode and could result in
premature replacement.
3. MicroPurge®Application Software
3.1 Installing the MicroPurge® App
The MicroPurge® App is a free to download app that can be found at www.qedenv.com, under the products tab
for the MP25/MP25T. Below are the steps to take to install the app onto your Android Device.
3.2 Connecting your MP25 or MP25T for the first time
The MP25 and MP25T are Bluetooth capable devices so the user can wirelessly display and log their data. Below
is how the user will connect their MP25 or MP25T to their Android tablet or phone.
1. Connect the 3m waterproof cable to the top of the sonde.
2. Connect the nine pin RS-232 connector to the Bluetooth Battery Pack.
3. Press the Black Power Button next to the RS-232 connector on the Bluetooth Battery Pack.
4. Open the MicroPurge Application, after opening the app will automatically start searching for all
Bluetooth Devices in the area. This can be filtered out, see section 3.7.2.
5. Select the Bluetooth Device that will be labeled with the same Bluetooth ID that is located on the
bottom of the Bluetooth Battery Pack. If the MP25 or MP25T does not initially show up, press the Find
Another MP25 button and the app will refresh the list of devices.
6. Once selected the app will auto direct to the Bluetooth settings on the device. Select the corresponding
device and if prompted for a password, enter 1234.
7. Return to the MicroPurge Application, and wait until the application initializes and brings up the local
Bluetooth devices.
8. Select the corresponding device, the app will automatically start scrolling data from the device. At this
point the MP25 or MP25T is connected, the device however is NOT logging data. To see how to set up
the PurgeScan Logging, see section 3.4.

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3.3 Home Screen
After successfully connecting your MP25 or MP25T to your Android Device, you will see a default list of
parameters and data scrolling across the screen. The device is NOT logging data at this point, see section 3.4 to
set up the PurgeScan Logging feature. Below is a description of each of the four buttons you will see on the
bottom of the Home Screen. NOTE: The column on the left is the most current set of readings. The scroll interval
(the time between live readings) can be set. It’s easiest to use the same interval for the Tablet Scroll Interval as
you use for the PurgeScan Logging Interval to avoid confusion, but this isn’t required.
3.3.1 Snapshot
The Snapshot feature will take a single data reading of the parameters that are currently on the screen. To view
the saved Snapshots, in the file explorer of the users tablet notated with MicroPurge, after selecting that there
will be a folder named PurgeScan Logs. Under that folder the saved snapshots will be appended to the most
recent PurgeScan log created. In the Annotation column will be the Note the user has entered into the Enter
Note option.

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3.3.2 Find another MP25
If this button is pressed after an MP25 or MP25T is connected it will disconnect the current device. This button
can also be pressed if a user is trying to connect to an MP25 or MP25T and the device doesn’t show up on the
list of Bluetooth devices.
3.3.3 View PurgeScan Logs
This button will bring up a dialog box allowing the user to view or download any PurgeScan Logs that have been
taken with the device. The PurgeScan Logs button located in the PurgeScan Menu is also another way to view
the save log files. In the upper left corner is the name of the log file, when pressed a list of other logs will appear
and can be viewed. These files will be downloaded onto the selected File Save Location, see Section 3.7.6 on
how to set the save location.
3.3.4 Settings
In the settings menu the user can control the PurgeScan Logging and Logs, Calibration of the sensors, Backup
Logs and app driven device settings.
3.4 Calibration and Calibration Logs
3.4.1 Calibration
Calibration of the sensors on the sonde is recommended each time the user goes out to sample for the day. The
calibration function on the sonde is located in the menu under Settings > MicroPurge Sonde > Calibrate. The
table below lists the parameters that can be calibrated on the MP25 and MP25T and the commonly used
methods and standards.

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Selecting Calibration Standards
For best results, choose a calibration standard whose value is close to what you expect to see in the water
you’re measuring. For example, calibrate with a 1413 μS/cm Specific Conductance standard if you expect to see
Specific Conductance readings between 500 and 1500 μS/cm in the field. Similarly, if your waters tend toward
being acidic (below 7) rather than basic (above 7), calibrate with a 4-buffer instead of a 10-buffer in addition to
the 7-buffer base calibration.
Sensor
Standard Method of Calibration
Available Calibration Solutions
Comments
Temperature
Never requires calibration
N/A
pH / pH Reference
2 or 3 points
pH 4, pH 7, pH 10
pH 7, pH 10 most common
ORP
1 Point
ORP Standard Solution, such as
ZoBell’s or Light’s solution
ORP standards can range from
200 –475 mV, any will work
Conductivity
1 Point
CD Standard, 0.5 Molar, 58670 Micro S
CD Standard, 0.1 Molar, 12856 Micro S
CD Standard, 0.01 Molar, 1412 Micro S
CD Standard, 0.001 Molar,147 Micro S
brackish/saltwater borderline
brackish water typical
freshwater very pure
fresh/glacial water
Reference Electrode
calibration not required
N/A
replace pH electrolyte
solution at routine calibration
Depth
Adjust for barometric pressure
N/A
Recalibrate at deployment
site for best accuracy
Turbidity
2 points
0 NTU, 10 NTU, 100 NTU, 400 NTU
calibrate near expected value
HDO (Optical DO)
calibrate at 100% saturated water
DI water -shake vigorously to
oxygenate
set BP before calibrating,
recalibrate at deployment site
for best accuracy
Temperature
The Temperature sensor is an electrical resistor (thermistor)
whose resistance changes predictably with temperature. The
sensor is protected by a stainless-steel tube. Thermistors are very
stable with time, and so do not require calibration.
Dissolved Oxygen (DO)
The optical dissolved-oxygen sensor uses fluorescence combined
with a membrane cap made of an oxygen active compound to
measure oxygen. When the sensing surface is exposed to water or
air, oxygen diffuses into the sensing surface according to the
amount of oxygen in the water. The sensor output is corrected for
the temperature and salinity of the water.

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The DO sensor can be calibrated for 100% saturation using either air-saturated water or water –saturated air.
Method 1 –Air-saturated water
1. Make sure that the barometric pressure setting is accurate (See Section X.XX)
2. Using a small jar or bottle with a lid, fill the container about halfway with tap water, cap it and shake
vigorously for about a minute, then remove the cap/lid and let the water stand for about five minutes to
allow air bubbles to float out.
3. With the sonde inverted and calibration cup attached, fill the cup until the water covers the DO sensor
by about ½” (1 CM) or so.
4. Wait 1-2 minutes for the temperature to equilibrate
5. Follow the calibration instructions for dissolved oxygen percent saturation (HDO % Sat).
Method 2 –Water saturated air
1. With the sonde inverted and calibration cup attached, rinse the cup with tap water and then empty
2. Place the storage cup cap upside down (threaded end up) on top of the calibration cup
3. Let the sonde stand in the calibration stand for 1-2 minutes for the temperature to equilibrate
4. Follow the calibration instructions for dissolved oxygen percent saturation (HDO % Sat).
The optical DO sensor in the MP25/MP25T system can be calibrated for zero oxygen as well as saturation. To
calibrate the zero point, follow the same steps as above for air saturated water DO using one of the three
following methods:
Method 1 –use a commercially prepared DO zero calibration solution or find instructions on preparation of a
sodium sulfite and cobalt chloride solution for zero oxygen calibration..
Method 2 –prepare zero oxygen water by bubbling nitrogen through water using a compressed nitrogen gas
source at low pressure and an aquarium air diffuser stone in a bottle of tap water for about 10 minutes.
Method 3 –Set up the MicroPurge with the flow cell and pass low-pressure nitrogen gas through the cell .
Optical dissolved-oxygen sensor maintenance is no more than occasionally
cleaning the sensing surface on the tip (the black material; about a centimeter
diameter) with a small soft cloth and soapy water. The tip has a very long
service life but must be replaced periodically, usually about once every four
years. If your SRF reports less than 100% or if you notice that the sensor’s
readings are getting noisy (i.e. jumpy), then it’s probably time to change the
tip by unscrewing the old tip and replacing it with a new tip and calibrating.
Conductivity/Specific Conductance (SpC)
The MicroPurge MP25 system uses the four-electrode method to
determine water electrical conductivity. Two pairs of graphite
electrodes are situated in a stable geometry. A constant voltage is

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applied to one of each electrode pair, and the amount of current required to maintain that voltage is measured.
As the conductivity of the water increases, the current increases.
The MP25 reports conductivity as Specific Conductance (conductivity standardized to 25°C). The conductivity
sensor is also used to calculate Total Dissolved Solids (TDS) and Salinity from the conductivity value.
The zero point for the sensor is set electronically, so you need only set the “slope” point for calibration:
1. Fill the calibration cup with your conductivity standard to cover the conductivity sensor. Tap gently on
the cup to make sure there aren’t bubbles trapped in the conductivity sensor.
2. Follow the MP25 software calibration instructions.
pH
pH is measured as the voltage drop across the glass membrane
of a pH electrode. A reference electrode is used to complete
the voltage-measuring circuit. The pH glass is specially
formulated to absorb water so that ions (particularly H+ and
OH-) in the water are attracted to the glass to offset the ionic
constituency of the pH electrode’s internal electrolyte. As a
result, there is a charge separation across the glass, and that’s
the voltage we measure. pH readings are automatically compensated for temperature.
You can choose a two- or three-point pH calibration. The two-point calibration is most common, using a pH 7
buffer and a pH 4 buffer if expected values are below 7 or pH 10 buffer if expected values are above 7. If you are
measuring in waters whose pH might range both above and below seven, you can increase your accuracy slightly
by choosing a three-point calibration (the third buffer should be on the other side of seven). To calibrate pH:
1. Rinse your sensors at least twice with the pH buffer you’ll use for calibration.
2. Fill the calibration cup with enough buffer to cover both the pH and reference electrodes.
3. Follow the MP25 Control Software calibration instructions.
4. Repeat steps 1, 2, and 3 if you choose to calibrate with one or two more standards.
pH electrode maintenance is minimal and only requires occasional cleaning of the glass bulb surface with a soft
cloth or soft cotton swab and soapy water. Do not use anything abrasive. The really important part of pH
maintenance is refilling the reference electrode.
pH/ORP Reference Electrode
The key to reliable pH, ORP, and ISE measurements is a well-maintained reference electrode. The MP25 system
uses a serviceable reference electrode with a replaceable electrolyte and reference junction. This combination
greatly extends the life of the pH/ORP probe as compared to probes that use integral reference electrodes with
gelled electrolyte. The free-flowing junction design also responds better in low conductivity waters.
Reference electrode maintenance is as follows:

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1. Remove the reference cap by unscrewing it from the reference sleeve using a coin edge and discard the
old reference electrolyte.
2. Fill the sleeve completely with fresh pH reference electrolyte (KCl saturated with silver chloride). Tap
the body of the MP25 sonde a few times to dislodge any bubbles.
3. Screw the reference cap back on to the sleeve. As you screw the sleeve into place, air and excess
electrolyte is forced out of the sleeve through the reference electrode junction (the white, porous circle
at the end of the sleeve). This not only purges bubbles from the electrolyte, but also displaces any
lodged particles or biological growth out of the junction.
Oxidation-Reduction Potential (ORP)
ORP is measured as the voltage drop across the platinum
membrane of an ORP electrode. The ORP sensor on the MP25
system is the 1 mm silver-colored dot you can see when looking
down at the pH sensor. The pH/ORP reference electrode is
used to complete the voltage-measuring circuit.
ORP electrode maintenance is also minimal, only occasional cleaning the platinum surface with a soft cloth
or soft cotton swab and soapy water. If the platinum is discolored, you can polish the ORP electrode with
very light abrasive, like 900-grit wet-and-dry sandpaper or a pencil eraser. You must be careful not to scratch
or polish the pH glass bulb.
ORP uses a one-point calibration as follows:
1. Rinse your sensors at least twice with the ORP standard you’ll use for calibration.
2. Fill the calibration cup with enough ORP standard solution to cover both the ORP and reference
electrodes.
3. Follow the MP25 calibration instructions in the prompts after selecting ORP_mV to calibrate.

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Turbidity
Turbidity is measured as the fraction of an infrared light beam that is
scattered at 90° to that beam. More particles in the water mean more of
that light is scattered, so the turbidity reading is higher. Any material
that accumulates on the optical surfaces of the turbidity sensor such as
solids and gas bubbles is indistinguishable from particles suspended in
the water, so most turbidity sensors have wipers to clean the optical
window (the small glass port on the end of the sensor).
Turbidity sensors require no regular maintenance, but you should check
occasionally to make sure the optical window has not been scratched or
damaged by cleaning or accidental contact.
Turbidity uses a two-point calibration; one point is zero turbidity and the other point should be a standard
approximating the turbidity of the water you intend to monitor. Zero calibration can be performed using a
commercial turbidity standard of 0 NTU or with distilled or deionized water. Note that distilled or DI water can
vary in clarity up to about 0.5 –1.0 NTU, so using it as a 0 NTU standard could affect accuracy of very low
turbidity readings.
Make sure you use enough calibration standard solution to cover the sensor’s “optical volume” –generally,
filling to near the top of the calibration cup when installed on the inverted sonde is sufficient. For the zero
calibration:
1. Make sure the turbidity sensor is fully immersed (i.e. at least 1 ½ inches of solution over the sensor) in
zero-turbidity standard and has an unobstructed optical path.
2. Follow the MP252 Control Software’s calibration instructions.
For the second calibration point:
3. Rinse your sensors several times with the standard you’ll use for calibration.
4. Make sure the turbidity sensor is fully immersed (i.e. at least 1 ½ inches of solution over the sensor) in
the standard and has an unobstructed optical path.
5. Follow the MP25 software’s calibration instructions.
A clean, smooth wiper means better measurements. If the wiper pad shows signs of deterioration, it can be
replaced. To change the wiper pad:
1. Using the 1.5mm hex key that comes with the new wiper pad, loosen the
small set screw on the wiper arm and gently remove the arm. Be careful
not to rotate the wiper arm as this can damage the internal gears.
2. Remove the wiper pad from the wiper arm and replace the pad.
3. Place the wiper arm on the motor shaft so that the set screw faces the
flat spot on the motor shaft.

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4. Gently press the wiper pad against the face of the probe until the
pad is compressed to roughly three quarters of its original thickness.
It is important that the wiper arm does not make contact with the
probe face –only the pad should be in contact. A gap of 0.5 mm
between the wiper arm and the probe face is typical when a new
pad has been installed. An easy way of setting the pad gap is to slide
a small piece of paper under the pad and then gently push down
until the wiper is just snug enough that the pad will hold the paper.
5. Tighten the set screw gently until snug. IT IS VERY IMPORTANT that you don’t overtighten this screw to
avoid stripping the threads, which would require replacement of the entire turbidity sensor.
6. NEVER rotate the wiper arm manually! This will strip the gears inside the wiper mechanism, which
would require replacement of the entire turbidity sensor.
Setting up the MicroPurge sonde for calibration
The MP25 and MP25T sondes are equipped with a storage cup that doubles as the calibration cup. The bottom
cap of the cup can be unscrewed and the sonde inverted for calibration. The cap can also be inverted and used
as a temporary lid for calibration of parameters such as DO % saturation in saturated air or water. The QED flow
cell kit includes a unique calibration stand that slips over the edge of the carrying case and holds the inverted
sonde as shown in the photo below.
Select Parameter to Calibrate
When beginning the calibration process, a dialog box will appear prompting the user to choose which parameter
to calibrate. After selecting press calibrate to open the next dialog box.

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Entering calibration data
1. Enter Calibration Standard into the text field and hit done on the keypad.
2. Pour Calibration Standard into storage/calibration cup until sensors are fully submerged.
3. Wait for the value to appear on lower right corner of dialog box. This typically takes about one minute
but could take slightly longer.
4. Hit OK
5. After this point the application will bring up another dialog box to calibrate to a second standard if
applicable (e.g., pH or turbidity). Follow the same steps above for the second standard. After successful
calibration of second standard the application will prompt for an optional third standard calibration for
pH; this is not necessary but is recommended for a more accurate data representation.

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Sensor Response Factor (SRF)
The Sensor Response Factor is created based off the calibration that was executed. This will tell the user how
near or far each individual sensor is out of specification, and may need possible replacement if number is far
enough out of specification. When you press the OK button to accept a calibration, the MP25 automatically
accepts your calibration if the SRF is between 60% and 140%. If the SRF falls outside that range, you will be
cautioned to check your standard value, make sure the sensor is clean, make sure the reading has stabilized, etc.
You can elect to accept any SRF value and continue with calibration.
Calibrating barometric pressure for Dissolved Oxygen (DO)
There are two ways to calibrate the Barometric Pressure (BP) on the MP25 or MP25T. NOTE: The MP25 and
MP25T sondes do not have depth sensors installed so the Get BP or Check BP buttons will not operate.
Method 1: Set the BP by typing in the correct pressure, if known, into the first test box. If entered the elevation
will be automatically estimated and shown in the second box. If you know the elevation at your location, the
calculated value in the second box should correlate with that elevation.
Method 2: The BP can be estimated by entering the altitude into the second text box. If entered the BP will
automatically be estimated and shown in the first box.

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3.4.2 Calibration Logs
Every MP25 sonde has a dedicated data file called CAL.LOG. The CAL.LOG will show all calibrations completed on
the sonde during its lifetime. In this file are the time and date of the calibration, the parameter calibrated, the
reading before the calibration was accepted, the reading after the calibration was accepted, the SRF, and a few
other details. These logs can be downloaded and saved onto the tablet of the user for documentation.