Oakton ORPTestr 50 Oakton ORPTestr® 50 Pocket Tester Operating Instructions

Operating Instructions

menu

hold

cal
esc

hold

®

ORPTestr

Applications

• Aquaculture

• Aquariums

• Boilers

• Car washes

• Ecology

Getting Started

The ORPTestr 50 Pocket Tester has been factory calibrated and usually works
well out of the box. However, after extended periods of non-use, it is best to
remove the sensor cap and soak the sensor in warm tap water or ORP buffer
for 10 minutes or so. A brief rinse with deionized (DI) water is OK, but avoid
soaking or storing in deionized water as this will shorten ORP electrode life.
Prior to taking the measurements, periodic calibration with certified standards
is recommended for best accuracy.

Temperature Settings

1. Press ON/OFF ( ) to power on if needed.

2. Press MENU/
The display shows Set °C/°F and Temp Cal.

3. Press HOLD/

4. Scroll down by pressing MENU/

5. Press HOLD/
temperature setting with a

Key Info
Scroll
Accept
EXIT

Backlight Settings

1. Press ON/OFF ( ) to power on if needed.

2. Press MENU/

3. Press HOLD/

4. Scroll down by pressing MENU/

5. Press HOLD/

v

MENU/

display shows Backlight.

Backlight ON increases readability in low-light conditions.

shows the selected backlight option with a

Key Info

menu

Scroll
Accept
EXIT

50 Pocket Tester

• Food sectors

• Hydroponics

• Labs

• Sanitation plants

• Steam generators

v

to enter setup window. Press HOLD/ to select Temp Set.

to select Set °C/°F. Display automatically shows °C and °F.

v

to toggle between °C and °F.

to select a temperature unit. The display shows the selected

.

Temp Set

MENU

Backlight

HOLD

Reset

CAL

v

to enter setup window. Scroll down by pressing

hold

Set °C/°F
Temp Cal

to select Backlight. Press HOLD/ to select Settings. The

to select Backlight. The display shows ON and OFF.

v

to toggle between ON and OFF.

to select the desired backlight option. The display

MENU
HOLD
CAL

Temp Set
Backlight
Reset

hold

Backlight

• Spas

• Studies

• Water and wastewater

treatment

Water quality testing

•

in pools and more

hold

°C
°F

.

hold

Backlight
ON

OFF

hold

hold

OFF

°C

ORP Calibration

Calibration should be done regularly, preferred once in a week. ORP tester
allows one point calibration.

1. Press ON/OFF (

) to power on if needed.

2. Dip electrode in about 2 cm to 3 cm into the calibration standard solution.

3. Press the CAL/ESC key to enter calibration mode. The CAL indicator will be
displayed.

4. Allow the reading to stabilize. The timer icon blinks during the reading
stabilization. Once the reading stabilized the timer stops blinking.

5. Upper display shows current measured value based on the factory default.

6. Lower display shows current measured mV with last calibration (if no
calibration is performed earlier both display shows the same measurement
value).

7. Press MENU/

v

to adjust the mV value to match the calibration standard

value.

8. Press HOLD/

to confirm the calibration or press CAL/ESC key to exit the

calibration without confirmation.

CAL

cal
esc

Place the tester in
the buffer to
start or press
to escape.

CAL

mV

189

189

CAL

RmV

844

25.0°C

ORP Measurement

1. Press ON/OFF ( ) to power on if needed.

2. Dip the electrode about 2 cm to 3 cm into the test solution. Stir and let the
reading stabilize. The timer icon blinks during this time. Once the reading is
stabilized, the timer stops blinking and
of the reading.

CAUTION: Testing dry samples is not accurate and can
lead to sensor damage or breakage. Soils must be wet
and free of particulates that may scratch the glass
sensor. Excessive force into dry samples can cause
glass breakage.

3. Note the ORP value or press HOLD/
reading, press HOLD/

4. Press ON/OFF (

8.5 minutes, the tester will automatically shut off to conserve batteries.

again.

) for 3 seconds to turn off tester. If a key is not pressed for

will appear to indicate the stability

to freeze the reading. To release the

ORP

RmV

844

25.0°C

User Reset

Reset the ORP calibration to the default using the user reset function.

v

1. Press MENU/

to select Reset. Press HOLD/ to select Reset. The display shows User

to enter setup window. Scroll down by pressing MENU/v

Reset and Factory Reset.

2. Press HOLD/

No and Yes.

3. Scroll down by pressing MENU/

4. Press HOLD/
reset option with a

to select User Reset. The display automatically shows

v

to toggle between No and Yes.

to confirm either No or Yes. The display shows the user

.

Key Info

menu

Scroll
Accept
EXIT

MENU
HOLD
CAL

Temp Set
Settings

Reset

User Reset
Factory Reset

hold

hold

No
Yes

Factory Reset

Reset the tester to the factory default using the factory reset function.

v

1. Press MENU/
MENU/

to enter setup window. Scroll down by pressing the

v

to select Reset. Press HOLD/ to select Reset. The display shows

User Reset and Factory Reset.

v

2. Scroll down by pressing the MENU/
Press HOLD/

to select Factory Reset. The display automatically shows

to toggle between the resets.

No and Yes.

v

3. Scroll down by pressing MENU/

4. Press HOLD/
reset option with a

to confirm either No or Yes. The display shows the factory

.

Key Info

menu

Scroll
Accept
EXIT

MENU
HOLD
CAL

Temp Set
Settings
Reset

to toggle between No and Yes.

hold

User Reset

Factory Reset

hold

No
Yes

Manual Temperature Setting

The MTS range is 0°C to 60.0°C (32.0°F to 140.0°F). User reset will set
temperature to default value 25°C or 77°F.

v

1. Press MENU/

to select Temp Set. Press HOLD/ to select Temp Set. The display shows
Set °C/°F and Temp Cal.

2. Scroll down by pressing MENU/
Temp Cal. Press HOLD/

3. The lower display shows the current measured temperature reading based
on the last set offset and the upper display shows the current measured
temperature reading based on factory default calibration.

4. Dip the tester into a solution of known temperature and allow time for the
built-in temperature sensor to stabilize.

5. Press MENU/
confirm the calibrated value as new temperature value of the solution.

Note: To exit without confirming the calibration, press CAL/ESC.

to select setup window. Scroll down by pressing MENU/v

v

to toggle between Set °C/°F and

to select Temp Cal.

v

to adjust the temperature value or press the HOLD/ to

Key Info

menu

Scroll

MENU

Accept

HOLD

EXIT

CAL

Temp Set
Backlight

Reset

hold

hold

Set °C/°F

Temp Cal

Temp Cal

23.4°C

23.4°C

hold

23.4°C

1065O100_MAN_35634-45.indd 1 9/5/2017 3:04:37 PM

HOLD Function

This feature helps to freeze the display for a delayed observation.

hold

button to freeze

mV

RmV
189

Press Hold
to release

25.0°C

2. Press HOLD/ again to

release the measurement.

mV

RmV
189

Press Hold
to release

25.0°C

mV

hold

RmV
189

25.0°C

1. Press HOLD/
the measurement.

mV

mV
189

25.0°C

Sensor Maintenance

1. Rinse the sensor with sensor storage solution after each measurement. Care
has to be taken not to damage the sensor’s glass electrode.

2. In aggressive chemicals, dirty or viscous solutions, and solutions with
heavy metals or proteins, take readings quickly and rinse electrode
immediately afterward.

3. If possible, keep a small amount of clean water or electrode storage
solution (NOT de-ionized water) in sensor cap to keep sensor hydrated.

Sensor Replacement

Replace the sensor module at the fraction of the cost of a new tester.

When the tester fails to calibrate or gives uctuating readings in calibration

standards, need to change the electrode.

1. With dry hands, grip the ring with sensor facing you. Twist the ring
counterclockwise. Save the ring for later use.

2. Pull the old sensor module away from the tester.

3. Align the four tabs on the new sensor module so that they match the
four slots on the tester.

4. Gently push the module onto the slots to sit it in position. Push the
smaller O-ring fully onto the new sensor module. Push the other O-ring
over the module and thread sensor ring into place by firmly twisting
clockwise.

Note: It is necessary that you recalibrate the tester prior to measurement
after a sensor replacement.

Replacing the Batteries

The pH tester 50 uses four AAA

1.5 V batteries.

1. To remove the battery cover,
See Figure 1. Clear the front
catch and then the back
catch, before sliding the
cover off.

Fig. 1: Removing battery cover

Fig. 2: Push to unlock

2. To remove the battery plate,
push the center tab towards
the front of the tester as
shown in Figure 2. Once
unlocked, remove the plate
to access the batteries.

3. Invert the tester upside down
to remove the batteries. Each
side uses two AAA batteries.

Fig. 3: Align tabs

Fig. 4: Push down to lock

Orient each battery with
positive terminal facing
downward.

4. To lock the battery plate, align
the small tabs (Figure 3) into
the guide ribs on the hous­ing and then press down.
See Figure 4.

Fig. 5: Battery plate unlocked Fig. 6: Battery plate locked

Warranty

This instrument is supplied with a warranty against manufacturing defects
for a period of one year from the date of purchase.

Return of Items

Authorization must be obtained from distributor before returning items for

any reason. When applying for authorization, please include information

regarding the reason the item(s) are to be returned.

We reserve the right to make improvements in design, construction and

appearance of products without notice. Prices are subject to change
without notice.

Self-Diagnostic Messages

Batteries are weak and need replacement soon.

stable error

over range
under range

Appears when calibration is attempted but the reading is not yet stable.
Wait for the reading to stabilize or manually confirm the calibration by
pressing enter.
The reading is above the measuring range of tester.
The reading is below the measuring range of tester.

Specifications

Specifications ORPTestr 50
ORP/RMV

ORP range –1000 to 1000 mV
Resolution ±1 mV
Relative accuracy ±2 mV ±1 LSD
Calibration points One
Calibration window ±200 mV
Calibration type Offset

Temperature

Temperature range 0 to 60°C / 32.0 to 140.0°F
Temperature resolution 0.1°C / 0.1°F
Temperature accuracy NA
Temperature compensation Manual
Temperature calibration window 0 to 60.0°C / 32.0 to 140.0°F

General Specifications

Display Graphics, dot matrix 80 x100 pixel
Backlight Yes, selectable (30 sec from last key press)
Auto off 8.5 minutes (from last key press)
Reset User / factory
Power requirement Four AAA 1.5 V batteries
Battery life >250 hours
Waterproofing IP67
Regulatory certifications CE, FCC
Ambient operating temperature 5 to 45°C / 41 to 113°F
Relative humidity 5% to 85% noncondensing
Storage temperature –20 to 60°C
Storage humidity 5% to 85%, noncondensing

Accessories

Ordering Code Product Description

35634-45 ORPTestr 50 pocket tester with case, lanyard, and batteries
35634-47 Replacement sensor module
35634-09 Replacement sensor cap
09376-00 Replacement alkaline batteries; AAA, 1.5 V. Pack of 12
17101-45 NIST-traceable calibration with data for pH testers
05478-60 YSI

®

Zobell solution

www.4oakton.com

1065O100_MAN_35634-45 August, 2017

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