Basically its a limestone hole dropping to 70'ish(I'm pretty sure I was in the 70s, but I don't have my log at hand as I'm out of town). The water isn't blue like most of the FL springs, but it
can still be very clear. The water has a deep green hue to it, very eary, but enjoyable. When I dove it last October, we had 60+' visibility. Water depths will of course vary according to local water levels. There are couple vents on the bottom of the limestone depression, but nothing you can squeeze into.
The run is usually pretty shallow, but contains quite a few mullet, bowfin, turtles, ect. At the end of the run, close to where it meets up with the river, there are remains of an old civil war boat(Madison, who's captain scuttled her to block the entrance of the spring run before leading troops into the wilderness).
I had alot of fun diving it, you can see everything you'd like to see with a tank though...