There is a very nice fish store in Charleston. It's located on Sam Rittenberg Blvd. I forget the name. The have a great stock of marine livestock. They also have a decent, well kept collection of FW fish and plants. The plants are limited and sell out soon, but if you call them, you can setup a good time/day to maximise ur visit. The best part about this store is very friendly and knowledgeble staff. They are not pushy at all. And yes they have ECOCOMPlete $29.99, if I remember correctly.
I can get you more details, if u r unable to find them on the internet.
I think you're referring to the place with the sign "FISH STORE" but it's called AGE OF AQUARIUMS and I love it there. The Staff develops good relationships with all costumers and they are very knowledgeable