Oakton PCTS5 Operating Manual

PCTSTestr

™

 5 Pocket Tester      

Features

•  Five measuring parameters: pH, conductivity, TDS, salinity,  

and temperature

•  Large easy-to-read LCD with 2-color backlight

• Replaceable single-junction sensor saves you money

• Auto power-off function conserves battery life

• IP67 waterproof rating

Operating Manual

1

2

3

4

5

6

(pH/Conductivity/TDS/Salinity/Temperature) 

Thank you for purchasing the Oakton PCTSTestr 5  

Multiparameter Pocket Tester. Please carefully read this  

operating manual before using the product to obtain an  

accurate and reliable test result and avoid unnecessary  

damage to the meter or probe.

pH Calibration

1.  Short press  /MEAS key to turn on the meter. Rinse the probe in 

distilled water and use tissue paper to gently dab off excess water 

(never rub or wipe the sensor).

2.  Pour a small amount of pH 7.00 and pH 4.00 buffer solutions in 

separate calibration bottles.

3.  Long press CAL/  key to enter calibration mode; short press  

/MEAS key to exit.

4.  Dip the probe in pH 7.00 buffer solution (SKU 00654-04), stir gently, 

and allow it to stand still in the buffer solution until a stable reading 

is reached. When stability icon () appears and remains on the 

screen (see Fig 1); then short press CAL/  key to complete the 

1-point calibration. The tester returns to measurement mode and 

indication icon “M” will appear at the bottom left of the screen, indi-

cating the middle point of calibration has been completed.

5.  To perform a 2-point calibration after the pH 

7.00 buffer, rinse the probe in distilled water 

and dry it. Long press CAL/  key to enter cal-

ibration mode.

6.  Dip the probe in pH 4.00 buffer solution (SKU 

00654-00), stir gently, and allow it to stand 

still in the buffer solution. When the stability 

icon () appears and remains on the screen, 

short press CAL/  key to complete 2-point 

calibration. The tester returns to measure-

ment mode and indication icons “L” and “M” 

will appear at the bottom left of the screen. 

7.  If necessary, rinse the probe in distilled water and dry it, and dip 

the probe in 10.01 buffer solution (SKU 00654-08) to complete 3rd 

point of calibration according to above steps. Indication icons “L”, 

“M”, and “H” will appear at the bottom left of the screen.

Notes 

A.  Tester will automatically recognize pH buffer solution. User can 

perform 1-, 2-, or 3-point calibration. But for the 1st point calibra-

tion, only 7.00 pH solution can be used. Then use other buffer 

solutions to conduct 2nd or 3rd point calibration. Tester will  

automatically recognize five kinds of pH buffer solutions.  

Refer to the table below:

Calibration

USA  

series

NIST  

series

Indication  

icons

Recommended

1-point  

1) 7.00 pH

1) 6.86 pH

M

Accuracy ≥0.1 pH

2-point  

1) 7.00 pH

2) 4.00 or  

    1.68 pH

1) 6.86 pH

2)  4.01 or 

1.68 pH

L    M

Range 

<7.00 pH

1) 7.00 pH

2)  10.01 or     

12.45 pH

1) 6.86 pH

2)  9.18 or 

12.45 pH

M    H

Range 

>7.00 pH

3-point

1) 7.00 pH 

2)  4.00 or  

1.68 pH

3)  10.01 or 

12.45 pH  

1) 6.86 pH

2)  4.01 or 

1.68 pH

3)  9.18 or 

12.45 pH

L    M    H

Wide measurement 

range

B.  For pH Calibration buffer solutions, we recommend that user 

replaces new buffer solution after each use to maintain the stan-

dard buffer’s accuracy. Do not pour the used calibration solutions 

back into the solution bottles in case of contamination.

C.  This pH probe will NOT give accurate and stable readings for dis-

tilled or deionized water. This is because distilled and deionized 

water do not have enough ions present for the electrode to func-

tion properly. Specialized pH probes and techniques are needed 

for distilled/deionized water measurement. 

D.  When testing purified water like spring water or drinking water, it 

will take longer for the readings to stabilize (typically 3 to 5 min-

utes) because there are very few ions left to be detected by the 

sensor in the purified water.

E.  Do NOT store pH probe in distilled water to prevent permanent 

damage to the probe.

F. For self-diagnosis information, please refer to table:

Symbol

Self-diagnostic information

Checking and methods to fix

Er 1

Wrong calibration solution 

or the range of calibration 

solution exceeds standard.

1.  Check if calibration solution is 

correct (1st point of pH  

calibration must be pH 7.00).

2.  Check if electrode is damaged. 

3.  Check if there is any air bubble  

in the glass bulb pH sensor.

Er 2

CAL/  key is pushed before 

measurement is stable () 

comes up and stays on 

screen).

Wait for the stability () icon 

to come up and stay, then press 

CAL/  key. 

*If you find any air bubble in the glass bulb of the pH sensor, simply invert the 

probe for a few times to remove it. The existence of an air bubble in the glass 

bulb will significantly decrease the accuracy of measurement. 

* The 1st point calibration must be 7.00 pH. Perform the 2nd point calibration 

(4.00 pH) immediately after the 1st point. Do NOT turn off the meter before 

you conduct 2nd point calibration. If the meter is turned off after 1st point cali-

bration, user will need to restart the calibration process with the 7.00 pH first 

and the 4.00 pH following after. Calibrating directly in pH 4.00 after turning 

meter off and back on will cause “Er1”.

pH Measurement

1.  Short press CAL/ key to turn on the tester. Rinse the probe in 

distilled water and dry it. Dip the probe in sample solution, stir 

gently, and allow it to stand still in the solution. Take readings 

after stability indicator icon () appears and stays on the screen.

Conductivity Calibration

1.  Press MODE/ key to switch to conductivity measurement mode. 

Rinse the probe in distilled water and dry it.

2.  Pour a small amount of 1413 μS/cm and 12.88 mS/cm  

conductivity calibration solutions into separate calibration bottles.

3.  Long press CAL/ key to enter calibration mode, short press  

/MEAS to exit.

4.  Dip the probe into 1413 μS/cm calibration solution. Stir gently, 

leave it to stand. Wait for the measurement stability icon () to 

appear and stay on the display (see Fig 1); then short press CAL/  to 

complete the 1st calibration. Tester returns to measurement mode, 

and indication icon “M” appears on bottom left side of display.

5.  After calibration, dip the probe in 12.88 mS/cm conductivity calibra-

tion solution. If the value is accurate, it is not necessary to conduct a 

2nd point calibration. If it is inaccurate, follow the steps above to com-

plete the 2nd point of calibration using 12.88 mS/cm buffer solution. 

Indication icons “M” and “H” will appear on bottom left side of display.

*1000 μS/cm = 1 mS/cm

Conductivity Measurement

Press  /MEAS key to turn on the tester. Rinse the probe in distilled 

water and dry it. Dip the probe in sample solution, stir gently, and 

allow it to stand still in the solution until a stable reading is reached. 

Take reading after stability icon () comes up and stays. Press 

MODE/ key to switch from Conductivity to TDS and Salinity.

Notes

A.   The TDS and Salinity measurements are converted from the  

conductivity measurements via a certain conversion factor.

B.  The tester can calibrate 84 μS/cm, 1413 μS/cm and 12.88 mS/cm 

conductivity calibration solution. User can conduct 1 to 3 points  

of calibration (refer to table below). Usually calibrating the tester 

with 1413 μS/cm conductivity standard solution alone will meet 

the testing requirement.

Calibration 

indication icon

Calibration 

standard

Measuring 

range

L

84 μS/cm

0 to 200 μS/cm

M

1413 μS/cm

200 to 2000 μS/cm

H

12.88 mS/cm

2 to 20 mS/cm

C.  The tester has been calibrated before leaving the factory. Gener-

ally, users can use the tester directly or users can test conductivity 

standard solutions first. If the error is large, then calibration is 

needed.

D.  For conductivity calibration solutions, we recommend that users 

replace new solutions after each use to maintain the standard 

solution’s accuracy. Do NOT pour the used calibration solutions 

back into the solution bottles in case of contamination.

E.  Temperature compensation factor: The default setting of the temper-

ature compensation factor is 2.0%/ºC. User can adjust the factor based 

on test solution and experimental data in parameter setting P4. 

Solution

Temperature compensation factor

NaCl

2.12%/°C

5% NaOH

1.72%/°C

Dilute ammonia

1.88%/°C

10% Hydrochloric acid

1.32%/°C

5% Sulfuric acid

0.96%/°C

F.   TDS and conductivity are linear related, and the conversion factor 

is 0.40 to 1.00. Adjust the TDS factor in parameter setting P5 based 

on the requirements in different industries. The factory default set-

ting is 0.71. Salinity and conductivity are linear related, and the 

conversion factor is 0.5. The tester only needs to be calibrated in 

Conductivity mode, then after calibration of conductivity, the 

meter can switch from conductivity to TDS or salinity.  

Conversion Example: if conductivity measurement is 1000 μS/cm, 

then the default TDS measurement will be 710 ppm (under the 

default 0.71 conversion factor), and the salinity be 0.5 ppt.

G.  For the self-diagnosis information, please refer to the  

table below:

Symbol

Self-diagnostic information

Checking and methods to fix

Er 1

Wrong conductivity buffer  

solution, which exceeds the 

recognizable range of the meter.

1.  Check if buffer solution is 

correct.

2.  Check if electrode is 

damaged.

Er 1

CAL/  key is pushed before 

measurement is stable ( comes 

up and stays on screen).

Wait for the stability () icon  

to come up and stay, then  

press CAL/  key. 

Setting the Parameters

When tester is turned off, long press  /MEAS key to enter parame-

ter setting. Short press MODE/ key to switch from P1 to P2…P8. 

Short press CAL/  key and parameter will flash, then short press 

MODE/ key to choose desired parameter. Short press CAL/  key to 

confirm parameter selection. Long press  /MEAS key to return to 

measurement mode.

Symbol

Menu setting

Selection

Factory 

default

P1

Select pH buffer standards

USA – NIST

USA

P2

Select Automatic Lock (HOLD)

Off – On

Off

P3

Select backlight

Off – 1 – On

1

P4

Set temperature compensation factor

0.00 to 4.00%

2.00%

P5

 Set TDS factor

0.40 to 1.00

0.71

P6

Select salinity unit

ppt – mg/L

ppt

P7

Select temperature unit

°C – °F

°C

P8

Restore to factory default

No – Yes

No

Notes

A. Select standard pH buffer solution (P1). 

There are two options of standard buffer solutions: USA series and 

NIST series. Refer to following chart:

Icons

pH Standard Buffer Solution Series

USA series

NIST series

Three-point 

calibration

L

1.68 pH or 4.00 pH

1.68 pH or 4.01 pH

M

7.00 pH

6.86 pH

H

10.01 pH or 12.45 pH

9.18 pH or 12.45 pH

B. Automatic Lock (P2)

Select “On” to activate auto lock function. When reading is stable for 

more than 10 seconds, the tester will lock the value automatically, and 

“HOLD” icon will appear on the bottom left of the screen. Press CAL/  

key to cancel HOLD on reading.

C. Backlight (P3)   

Select “Off” to turn off backlight function, “On” to turn on backlight 

function, or “1” to have backlight last for 1 minute.

D. Temperature Unit (P6)

Select °C or °F; the factory default is °C.

E. Factory Default Setting (P7)

Select “Yes” to recover instrument calibration to theoretical value 

(pH value in zero potential is 7.00, slope is 100%), parameter setting 

return to initial value. This function can be used when instrument 

does not work well in calibration or measurement. Calibrate and 

measure again after resetting the unit to factory default status. 

6.6

7

pH

pH

☺

☺

Figure 1

Keypad Functions

Short press = <2 seconds         Long press = >2 seconds

MEAS

1.  Short press to turn on the tester and long press to turn  

off the tester.

2.  When turned off, long press to enter parameter setting mode. 

3.  In measurement mode, short press to turn on backlight.

MODE

1.   In measurement mode, short press to switch parameter from 

pH to Cond to TDS to Sal.

2.  In mode setting, short press to change parameter  

(unidirectional).

CAL

<

1. Long press to enter calibration mode.

2. In calibration mode, short press to confirm calibration.

3.  When measured value is locked (HOLD icon), short  

press to unlock.

Preparation Before Use

If it is first-time use or the tester hasn’t been used for a long time, pour 

some 3M KCL solution in the probe cap (about  

1/5 of the probe cap) and soak the probe for 15 to 30 minutes.

When not in use, we recommend storing the probe in 3M KCL stor-

age solution (preferably Oakton Electrode Storage Solution SKU 

00653-04) in the probe cap to maintain the sensor’s accuracy. But 

even if stored dry, it won’t do any permanent damage to the sensor. 

It will only temporarily cause the probe to lose its sensitivity, which 

can always be restored by soaking in the storage solution.

If the soaking solution was contaminated, please replace immediately.