I only recently learned of the "calibration" feature on that system, mine had gotten to the point it would report half as full, I usually only keep it around half and it's on a hoist so gas goes in 5 gallons at a time, last week I ran down to 1/8 and filled it to the top and it seems to be accurate again. I kinda don't love this system, we're not on a private pond so the fuel management system likely not an option either?