Originally Posted by Tunce the traveler
You got it and the display panel never worked! I just check the toilet hole and the low point tub for water about my 5th day into camping as a general rule.
Puh-leeez don't get started on the perfect accuracy of the level displays.
I've found the blackwater level jumps to 2/3 full after 2 uses of the toilet then gives reasonable reading after the first full day of boondocking.
I don't bother with the FW reading. The tone of the water pump is much more accurate.
Grey water level? When the shower doesn't drain...
And on topic:
You won't know the useful
capacity of your tanks until you completely fill them and then measure how much can be reasonably drawn out.