Why does the soil moisture meter show different readings at the same location?Updated 17 days ago

The device reading is a relative soil moisture indicator, they are aligned to have same characteristics in the sensor design, thus there is difference between the wh51 and wh51L.

If you want the device of WH51L to be same as your wh51, then you can turn on custom calibration mode on the APP side, and you can adjust the 100% AD so that you can linearize the sensor with another slope. For more details. You can refer to the AD and custom mode calibration. This calibration won’t calibrate on the display of your wh51L, but on the dashboard:

The AD value displayed on your tile underneath our soil moisture sensor is the raw data measured by the sensor, and this can be utilized by users running the system in "custom" mode. 

Our standard reading, based on factory calibration, is the default soil level displayed: absolute dry air (0%)and most damp (100%) submerged in water.

By configuring the device to operate in custom mode on the gateway side, you can adjust the sensitivity of the readings to your specific needs.   

1. record your absolute dry(0%) and most damp soil (100%) AD values.
2. On your "ecowitt" app, tap on "..." from the app dashboard, go to the "calibration" page, and choose the "multi CH soil" sub-page. 
3.  With the custom mode enabled,  fill in the two 0% and 100% AD values you obtained and apply save. It's that straightforward. 
4. your soil moisture reading is now adapted to your new calibration.