Why do my measurements have the date 1970?

The PoolLab is delivered without default date. The date is set to the system time of the smartphone/computer each time the app and software are connected. Before initial operation, after an update and after a battery change, the PoolLab must be manually connected to the software/app so that the PoolLab time can be set correctly.

Measurements that have already been imported with the wrong date can be edited manually so that the measurements are listed chronologically again.

Why can't I connect to the PoolLab?

The PoolLab uses Bluetooth 4.2. On Android the app needs the location permission to scan for PoolLabs. Depending on the Android version, Google also requires location to be enabled on the smartphone. Additionally, the PoolLab uses a protocol that does not support pairing in the Android settings.

Make sure that the app has the location permission (Settings > Apps > LabCom > Permissions > Location), that this is enabled in the settings (or the status bar menu) and that Bluetooth is enabled on the PoolLab itself.

We do not collect any location data, but the permission is only required for using Bluetooth 4.2 within the app. is the link to the Android documentation: https://developer.android.com/guide/topics/connectivity/bluetooth#Permissions

My PoolLab is stuck in update process at ~7%, what can I do?
Please try the following procedure
(on Android please disable the 'smart lock' Bluetooth feature for the PoolLab)

1. close the app (not running in the background)

2. in fact the PoolLab shows the 'Bootloader' screen press the 'pH'-button for 2 seconds to reboot the PoolLab in normal mode

3. unpair the PoolLab in the device settings of your mobile device

4. turn off Bluetooth on your mobile device and turn it back on after 10 seconds

5. restart the PoolLab app

6. reconnect the PoolLab via Bluetooth (in the app, not in the Bluetooth settings of your device)

If this doesn't solve the issue try the following
(force bootloader mode)

1. press and hold 'pH', 'fCl', 'TA' and 'CYA' buttons and release them simultaneously after 1 second

2. turn off Bluetooth on your mobile device and turn it back on after 10 seconds

3. restart the PoolLab app and reconnect to the PoolLab (note: now displayed as 'PoolLab OTA')

Note: On Android in some cases it can help to restart your smartphone or tablet before reconnecting to the PoolLab

If nothing above helps please try to remove the PoolLabs batteries for 1 minute.

Does a scratched cuvette negatively affects the measurement result?

As long as the cuvette is not scratched in the upper part, but e.g. only at the bottom where the tablet is crushed, the measuring result is not affected. Only in the upper part, where the LEDs for ZERO and TEST light up, and on the opposite side (sensor) no scratches should be visible.

Which parameters can be tested with salty water?
The following parameters can be tested in salty water:
参数 Fresh Water Saltwater Seawater
Active oxygen
Chlorine dioxide
Cyanuric acid
Total hardness
Calcium hardness
pH值 *
Hydrogen peroxide
* Special case pH measurement

Depending on the salt content of your sample, the measurement result must be corrected according to the following scheme:

1 molar = -0,21 pH值

2 molar = -0,26 pH值

3 molar = -0,29 pH值

where: 1 mol salt (NaCl) = 5.8% = 58.4 g/l

Pools with salt electrolysis are not affected.
In salt electrolysis, a maximum of 7 g/l salt is used, far less than 1 mol (58.4 g).

Why is my total chlorine lower than my free chlorine?
Possible cause

When measuring free chlorine, the solution was still slightly turbid after the addition of the DPD 1 tablet, e.g. due to very hard water, or air bubbles were formed. Both causes less light to reach the sensor and therefore the measured value is higher. During the total chlorine measurement (2 min waiting time), all suspended particles have usually settled and air bubbles have also risen, so that the value is lower again.
In addition, each measurement is subject to certain tolerances (see instructions for use). In this respect, even if the proportion of bound chlorine is very low, a slightly lower value for total chlorine compared to the value for free chlorine can be determined due to the measurement tolerances.


Please simply press the 'fCl' button again after receiving the measurement result (do not empty the water!) and interrupt the countdown by pressing the 'on/off' button. Repeat this until a stable value is displayed.

Why are there no target values in the instructions for use?

Since the PoolLab is offered worldwide and since there are even nationally different specifications for target values, every manufacturer of water analysis equipment is wary of making target recommendations.

A small example:
The German bathing water regulation prescribes a chlorine value (free) between 0.3 and 0.6 mg/l, which would certainly quickly lead to considerable problems in private pools without control and dosing technology. Chlorine values of max. 0.6 mg/l in southern countries would almost be criminal. The same applies to the other disinfection parameters.

What are potential interfering factors in my measurements?
  • Make sure that photometer tablets (black print on the back of the tablet blister) and no RAPID tablets (green print on the back of the tablet blister) are used
  • ZERO (reference value) must always be made without tablet and with the water to be measured, otherwise incorrect measured values
  • ZERO and TEST always with light protection cover in place
  • Make sure that there are no air bubbles in the sample water for ZERO and TEST.
  • When measuring, do not hold the PoolLab at an angle but straight, otherwise the water to be measured will not be fully within the range of the LED/sensor
  • If the cuvette is scratched or contaminated or even dyed, it must be replaced with a new cuvette
  • Do not use expired tablets
  • The cuvette, cap and stirring rod must always be clean and free from any residues of previous measurements, especially after insertion of the DPD 3 tablet
  • Always take the water to be measured from a representative point in the pool. Not near the skimmer, not near the inlet nozzles, not from the ground or the surface but at least 20 cm below the water surface and if possible from the centre of the pool.

Why do I get unstable values during pH measurement?
Possible causes
  • If more/less than 10ml of sample water are used
  • If the tablet is not completely dissolved

In addition, alkalinity values below 40 mg/l and a turbid solution interfere with the pH measurement.

Also salty water can lead to incorrect measurement results. A manual correction can be found under the point 'Which parameters can be tested with salty water?'

Why do I get increasing values when I repeat the free chlorine measurement?

If you press "fCl" again after displaying the measurement result, the displayed value may increase continuously.

This is because the reagent (DPD N°1) reacts with all substances that have an oxidative character, including atmospheric oxygen, for example.

In most cases, however, it is the case that there is a high content of combined chlorine, which is gradually transferred over time to react with the DPD 1 tablet.

Free chlorine values should therefore be measured without fail within 1 minute after complete dissolution of the DPD 1 tablet (time until the result is displayed).

Results displayed after this time may not be meaningful.

"ppm" is equivalent to "mg/l".

Ppm stands for "parts per million". One milligram is one millionth of a kilogram (1 liter = 1 kg).

Application note for unstable measurement results

Depending on the nature of the water, e.g. high hardness values, the countdown set by the device is not sufficient until particles and turbidity have settled. We therefore recommend to start the measurement again without changing the water by pressing the measuring button and to interrupt the countdown by pressing the On/Off button. Repeat this procedure until stable values are displayed.

Why does the DPD tablet not work if there is too much chlorine in the water?

DPD tablets (all manufacturers!) only work up to approx. 10 mg/l chlorine in the sample water. Values above 10mg/l cause the DPD reagent to bleach out again, up to colourless.

If you consider that 10mg/l in a small pool with only 5,000 liters means just 50g, i.e. 2 1/2 times the weight of a letter, it can quickly happen, especially for inexperienced pool owners, that this value is exceeded. Often the DPD tablet is blamed and as 'proof' a bucket of water (5 litres) is mixed with a lot of chlorine, then measured and the same effect is found. At 5 litres, the limit value is then only 0.05 grams, i.e. approximately one grain of chlorine.

Even tap water cannot be used for comparison, because German tap water does not contain chlorine.

Fortunately, it is easy to detect overchlorinated water. Instead of filling the cuvette completely, the user should only add a few drops of water to the cuvette and dissolve the DPD tablet in it. If these few drops turn red, the tablet is working properly. If the solution decolorizes when the cuvette is filled, the water is highly chlorinated. In this case the water sample must be diluted before measurement.

Why can't I install the app?

The PoolLab app is supported on Android 4.4.1 and higher. Older versions or smartphones with not suitable Bluetooth environment are not supported.

Update your phone or buy a newer phone

What do 'OR' and 'UR' mean?

The 'pH' parameter has a measuring range of 6.5 - 8.5 pH. Measured values outside this range are indicated with 'OR' (Overrange) or 'UR' (Underrange). This is not an error but indicates strongly acidic or strongly alkaline water, which requires the use of pH-Plus or pH-Minus. It must also be ensured that the alkalinity value is > 40 mg/l CaCO3 so that the 'Phenol Red' reagent reacts correctly.

'UR' cannot occur with all other parameters, as these start at '0'. However, 'OR' is quite possible if the measured value is above the measuring range of this parameter. In this case, the water sample must be diluted before measurement (see 'Dilution').

Bootloader No firmware! Run update

If this message appears, it means that the update went wrong and no executable firmware is installed on the device. Therefore a successful update must be installed. Please proceed as follows:

1. Start the LabCom App

2. Connect your PoolLab under 'Connect Photometer'

3. Confirm the update popup

4. Select the 'PoolLab OTA' from the Bluetooth list

5. Confirm the update popup again

6. Wait until the update has run successfully


- Do not quit the app

- Do not move the app into the background

- Do not let the display turn off

Why do I have moisture under my display film?

In a few cases, we have found that the keyboard foil in the area around the display is not pressed down properly during production and then, e.g. due to varying pressure during air freight, does not seal sufficiently against water.

Fix the keyboard foil once around the display area with finger and pressure Make sure that the battery compartment is properly screwed down