Since most aquatic gardeners are also terrestrial gardeners, you should try your best to also see the Atlanta Botanical Garden while you're in town. It's one of the best, and the new state of the art orchid houses are amazing with both highland and tropical sections. There are Nepenthes in there bigger than your forearm. Also, the Camellias will be beginning to bloom in the woodland garden, and they have some exceptional dart frog paludariums in the lobby of Fuqua conservatory.