@_Steve posted:Yeah I did a lot of pressing on the tub… and even drilled several small inspection holes. Apparently I did not correctly interrupt the data.
I “calibrated” pretty much as you describe…. Measured volume, set the appropriate calibration depth value, add another known volume, wash rinse repeat until full. I could not establish a single depth value that was accurate for all volumes. Sooo at least for now, it is reasonably accurate for the bottom 1/3.
Did you find the bubble level setting in the app? I fooled it to interpret that the sensor was a close to level as I could. That setting is what I attribute the accuracy at higher levels. I don't know the sensor's ultrasound cone angle is but setting a "level" baseline made a difference in my installation since my sensor is mounted on a sloped pat of the tank.