In Charleston I
believe the choice is either Charleston Scuba or Low Country Scuba.
I've been to CS and planned to dive with them but were cancelled by weather the only day we could go. Seemed like a decent operation - they called us early that morning to advise that they had to cancel. They're in south Charleston - over the bridge.
- Charleston Scuba - Full Service PADI 5-Star IDC
Low Country would be slightly closer from Columbia - they're in Mt. Pleasant.
Lowcountry Scuba Online
It's mostly wreck diving although there are some ledges. The ledges are maybe 10-12' tall and jut out of the sandy bottom so they attract fish. But not like the schools around the wrecks in my observation. The farther out you go the better the vis also.
We dove with and I recommend Express Watersports in Murrell's Inlet - south of Myrtle Beach - but that would add an hour to your drive. The Litchfield Beach/Murrells Inlet area is pretty nice if you wanted to overnight - it's a resort destination south of MB.
The vis in the Low Country videos is pretty much how it looked off Murrell's Inlet - sandy bottom broken up by an occasional wreck or ledge. On the ride out (an hour+) I asked the DM what was under the boat? "Sand and more sand"...
There's also the blackwater teeth dives in the Cooper River. I may be incorrect but I thought that's where the teeth are found - not out at sea. The Cooper is tannic so vis is about what's shown here:
Cooper River Dive Charters - CooperRiverDiving.com Also I believe there may be gators. I know next to nothing about this.
In August the water is probably going to be really warm. We saw 84-85
o at 60' over the 4th of July. The only reason for a skin/light suit might be the Jellies - at one site there was a lot of them.