This tank is claimed to hold water been sitting on trailer for 6 months. Claimed to be 250 gallons and wants $200, but measures 72L x 18W X 24H. I guessed it was 180 gallons so he is willing to take $100, I said OK and told will return with $100. But now that I checked online at home the volume calc say only 135 gallons. The tank has no cracks or chips and the seals look good as claimed and looks like it will hold water as claimed. Also comes with 4 heavy original glass covers. He is willing to include stand original made of particle board but its swollen damaged from rain so no good, don't want it. What do you all think? Should I go lower say $75 claiming the tank is actually 135G not 250G?