[Gmecm] OT - refrigerants

[David Allen]

This is OT but we have a very diverse knowlege base here!

I came home to find that the refrigerant has been lost from my house central
A/C.  The leak is easily fixable.

What alternative refrigerants are available to replace R22?  Any experiences
or recommendations?  I am certified to buy refrigerant.

I remember something about DuPont MO99 / R438A. Any experiences with this 
product?

Thanks for any and all input!

Sincerely,
David