You'll just have to pay a lot more to refill the tank than five years ago. Liquified Petroleum Gas (LPG) is mostly propane with smaller amounts of other flamable gasses like butane and ethane. When stored in a suitable container, LPG doesn't react with anything, separate, get contaminated, or "age".
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There should be no problem with the current tank load.. Propane, unlike gasoline, does not spoil rapidly.
Refilling may require recertification (I do not know) if you look at the tank the cert date is stamped on it.. And I'm sure someone can tell you how long a certification is for (I can not) RE-Certification is easy. and to be honest may well save you money in the long run.
here is how to do it
First http://www.blackle.com (or just go to Google the usuall way) and type the word PROPANE followed by your zip code
Now,, Fing the places that have really big tanks, and trucks that go out to fill the propane stores with smaller tanks.. These are the propane delivery services.
Visit one.
Take the tank with you
They (usually) can re-cert them for you
AND.. When they tell you what THEY charge to fill the tank.. You are very likely to get real upset with whomever you have been going to and never go back there again (I've seen the suppliers be less than half the price of the "Dealers" in the area)
So the re-cert, will pay for itself as you re-fill the tanks at a far lower cost.
Three places I knwo of.. PIT-STOP in Quartsite AZ may be able to do it (not sure)
Carmichael's Propane, Teknosha, MI (You can stay at the TE-KON, the first "Truck Plaza" while they do the tank, they are just down the road)
Parker's Propane in Flint MI (Been there, where I fill my tanks)
Oh, Carmichael's.... They bought the farm I grew up on
Nothin adds excitment like something that is none of your business
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