I understand that +/-25cm (not meters) is the accuracy of air pressure equivalent altitude. And that is precisely what I was trying to measure but as I described in my previous post, I am getting a much larger range over a 5 minutes period (around 70cm).
How can the sensor be used as an altimeter in a drone then?
Regarding your description of the water level measurement, it suggests that the sensor is measuring hydrostatic pressure. Can this sensor be mounted underwater?