archman:Although not on the same scale as large Pacific kelps, you can find tall aquatic vegetation stands in many of Florida's springs. Some of the macrophyte species can exceed several meters in height, and they're often chock full of little fishes, invertebrates, the odd turtle... occasionally a manatee.
There's similar diving to this in a few places in Texas too. Clear Springs Scuba Park, Lake Amistad, Aquarena Springs, Comal and San Marcos rivers. Lake Amistad possesses hydrilla stands so dense, it is physically impossible to penetrate them. You have to float over the tops, and drop down where it's clear. The stands I've seen are 4m tall, broaching the surface.
Will be going to FLA in June / July - can you recommend any springs for such dives?
Dan