Merritts is Ok. I grew up in Marianna. The Hydrilla has really been a problem on the pond. Lake Seminole is always a good destination for Crappie. Third Ramp on River Road, and out to the east, they call it the Stumps, flooded forest, is always a killer.
As far a diving the Mill Pond, they are getting away from that. The springs dont flow hard enough to move the silt out so it is pretty much to dangerous these days.