On Tue, 5 Jun 2012 05:24:38 -0700 (PDT), DerbyDad03
wrote:

I have a gas grill that goes through an O-ring about once a year.

If you look closely at this picture you can see an O-ring where the
connector screws into the regulator.

http://www.clagrills.com/partsphotopages/00920.htm

About once a year this O-ring get chewed up and begins to leak. I've
bought the O-ring at a hardware store but I'm wondering if there is
someplace else I should be getting them from.

Is there a special material for gas grill O-rings?

Nothing special that I'm aware of, but why are they going bad? I've
been using propane appliances for decades and have never had to
replace one.

Check the mating surface on the tank. Could be a burr or grit or
something causing the ring to get eaten up. They should last years
under normal use.