Originally Posted by i3dm

I see, this makes the unit more complex and more expensive, which is a route i do not want to go.

I can definitly code the integral function on pump voltage, but we need to think about calibration.

One option that wont require calibration is simply summing pump voltage, and then whichever number you get as "full tank capacity" is now your full value, take 20% off that and thats your threshold for landing.

For example my tank is 5000ml.
But because i didnt calibrate, full tank actually "counts" 10,000ml. So i will simply set my alarm to 8000ml and be done with it.