Sorry about reviving an old thread but I was frustrated last night trying to start a thread about this water tank.
I filled the tank until I couldn't get another drop to go down and then drained into a 5 gallon bucket 5 times. I did this 3 times getting the same result each time. The biggest reason for doing this was because after my last trip (2 weekends ago) when I drained the tank at home the level indicator showed 2/3 full but the tank had nothing left to drain and the pump was sucking air. I put bleach into the tank and begin to fill hoping to clean the sensors and again after 6mins the tank was full and running back out the fill tube. The tank indicator showed full and the pump filled the lines. I drained the tank into a 5 gallon bucket 5 times and no more came out. All season long since we started camping the 1st week of May we would run out of water if we weren't hooked to a bib. I kept blaming the wife for taking too long of a shower. When our tank ran dry we would show 2/3 full gray water and 1/3 - 2/3 black water. I measured the tanks yesterday and both will take 35 gallons each and then some. 8 gallons in the black water shows 1/3 full. 16 gallons in the gray water shows 2/3 full. That is why I checked the holding tanks to see if the were the advertised sizes and they are, just the level indicators are way off. I called GenRV today and have a Nov. 9th noon appointment to see what's going on. I got her winterized today so we'll find out in a couple of weeks. Sorry about the endless rambling.
2012 Silverado 2500HD 6.0 Gas 4.10 gears
1986 Buick Grand National 4400 Actual Miles
(yes I bought it new)
2015 Crusader 28RL
Days camped 2014 33
Days camped 2015 42