Thanks you all for the feedback. More than likely the tank's volume is indeed less than advertised. With marketing the way it is it's too easy to lie - I mean accidentally post inaccurate specifications. Like someone mentioned funny how it errs in favor of sales.
I'm sure there could be some build up in the tank but 41%? Plus the RV is in such good shape it looks new. So probably little used.
I also struck the tank's bottom with the wand when washing down the insides. What I'll do is look for specs on the outside and not finding that attempt to measure the outside and do a little math.
Fortunenately it's just us two and we haven't had a shortage of ullage thus far.
Reg
