I have an RV 10 and dual G3 X touch screens. I did the fuel calibration on both tanks last night and that went flawlessly. However when I drain the tanks the indication is that I still have 30 gallons in each tank even though both are empty. Each addition of fuel lowered the displayed input voltage giving a nice graph. However now with the tanks empty the screen indicates 30 gallons yet in each tank and the input voltage is lower then I saw at any point last evening. my fuel sender's gave appropriate ohms readings before I install them in the tank and both tapped the upper or lower portion of the tank when I inverted the tanks indicating the senders were moving appropriately. why would the indicated input voltage be reading lower than the lowest reading I received last evening at the 30 gallon mark. Obviously that is why the screen is indicating full tanks even though they're empty.