Just in case anyone needs some references for future CO2 tank refills.
Georgia Paintball on Barrett Parkway filled mine yesterday... $15 for 5lbs.
Brew Depot on Old Alabama and Mansell is my usual go-to but they're closed Sundays (also ~$15 a fill IIRC)
You can also try Schoolhouse Beer in Marietta, but he's kinda expensive ($25 for the fill).
Also one thing I've started doing recently is weighing my 'empty' bottle before and after so I make sure to get the full 5lbs... the paintball place was spot-on 5lbs and I've not had issues as Brew Depot either (can't speak for Schoolhouse though).