Trying to figure out the math on the grey/black and water holding tanks, on our previous outing our fresh water tank was reading 2/3 full, our gray water tank was reading 2/3 full and the black water tank was reading 1/3 full, according to the trailer specs the fresh water tank is 42 gallons, the grey is 30.5 and the black is 30.5 as well, doing the math on these I don't see how the grey water tank can be that full when we never used that amount of fresh water? Maybe some one can help verify this, I know that the sensors in these tanks are not that accurate but according to my calculations these are way off.