Ron, if you do get a bigger tank be aware that anything bigger than about 100 gallons (I think the actual number is 124) cannot be up next to a building.  Speaking as the guy holding the fire hose I'd rather none of them were close to the building. Fire code says 25 feet but 10 is allowable in some circumstances.  I lean toward 50 foot minimum isolation.

Also needs to be on a solid non-combustible foundation (not building blocks) 10 feet from a driveway, buildable property line, high voltage light wire, etc  Oh, and while not part of the code, don't set it on the septic tank lid