Where can I but a propane buffer in Atlanta area?

I own and operate a pretty big grocery store. I previously used a company to clean and buff my floors daily but this expense was too expensive. I am currently mopping the floors but their are black marks on the floor that I believe only a buffer would take out. What size buffer do I need and where can I buy one cheap!? When I used a company to buff the floors, the guys always brought their own silver propane tank. Please let me know! Thank you!