Reply #4: One Note On #1 and #2

[ProfessorGAC]

The tanks are buried sufficiently low that ambient temperature diffences of a few degrees won't matter. Yeah, th edifference between summer and winter will be significant, but the difference between 20F in the morning and 28F in the afternoon won't matter to a measurable degree. The tank will take a very long time to equilibrate, given the lack of mixing.

#2 is questionable. Highly reputable gas stations use water and sludge sensors. And, since tanks are now polymeric, rather than metal, the old sludge problem is far less than it used to be. If the tanks show water on the sensors, they have a legal su(at least in Illinois), to have the tank sucked clean and new gas put in. So this isn't the problem it used to be.

3 and 4, i like.
The Professor