There are a lot of ARC sponsors with a nice selection of acans and brains. Best bet might be to call some and ask what they have.
In the midtown area, you might look at Warehouse Aquarium, Keen Reef, and Atlanta Reef inside the perimeter. Einstein would be a good choice in the general area as well, as they are just outside the perimeter in the 285/LaVista Rd area, not too far from the other three I mentioned.
If you are willing to drive farther, many of our other Sponsors have great coral selections as well.
Dave