I don't know the size of the window, but the tank holds 6.33 million gallons (24 million liters) of water. The pump room contains 36 pumps, with another 34 pumps operating the protein skimmers. Together they are capable of moving all 6.33 million gallons of water through the filtration system every 60 minutes. The deepest section of the exhibit is 9.1 meters (30 feet) deep.
There are all sorts of construction photos and wonderful statistics in the book "Bringing the Ocean to Atlanta: The Creation of the Georgia Aquarium".
The large window is 23 feet tall and 61 feet wide, their literature claims it is the second largest aquarium window in the world, but it is the third. The largest is at Dubai Aquarium at 27 feet tall and 107 feet wide. The Okinawa Charaumi Aquarium is second with a window that is 29 feet tall and 74 feet wide. I am not sure if there are any other bigger ones elsewhere, but I know that Monterey Bays Outer Bay window is 17 feet tall and 54 feet wide.
I'd love to see a complete list of all the species in the Ocean Voyager exhibit as there are so many fish species in there that I don't know the names of!