How to Measure Under Water

Step-by-step instructions to use Photone under water

Photone can be used under water with proper preparation and adjustments. Follow these steps for accurate underwater measurements:

Step 1: Waterproofing

Even if your device is water-resistant, we recommend additional protection. Place your device and eventual diffuser in a clear plastic bag. Submerge most of the bag to remove air, then seal it.

Putting your device in a clear bag ensures that your whole setup is waterproof.

Step 2: Calibration

If measurements differ significantly with and without the bag, calibration is recommended. Otherwise, you can skip this step.

First, take a reference measurement without the plastic bag under a stable, bright light source. Then, perform the calibration as follows:

The three steps steps to calibrate for the plastic bag in front of the camera

Once calibrated, the app adjusts for any light blocked by the plastic bag.

Step 3: Touch Screen Adaptations

Underwater use can cause the touch screen to malfunction, leading to erratic app behavior due to false touch recognition.

To address this, we recommend our Pro settings in the app. Within Pro settings, disable hold mode to minimize touch screen issues. Additionally, activate advanced readings for a simplified readout of the measurements.

The Pro Settings we recommend to enable for underwater usage

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That's it! You can now use Photone as an underwater PAR meter.

Underwater Accuracy

Photone is almost as accurate under water as it is in air. We compared Photone on various iOS and Android devices and measured median deviations of less than 3% when compared to our high-end reference equipment.

The results showing the deviation of Photone compared to our Apogee reference sensor under water

If you want to learn more about the accuracy of Photone under water, we recommend reading through the detailed test we published on our blog.

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