Not too keen on Hudson...this is what eeandiver had to say....
Just a heads up on Hudson Grotto. It's normally very dark below 50' and at the 100' platform it's pitch black. The best vis I have seen at the top circut line is 20' and the bottom temp is usually in the 60's. With the cold weather the suface temp should be about 70 or lower.
It's an excellent place to do low/no vis diving, line work at depth (100'+) and similar skills. $15 to get in makes it worth a day but don't expect Ginnie clear water. Look up more info at
www.floridacaves.com
BUT Crystal springs looks good...this is from their website!!
Ginnie Springs has often been called "the world's favorite freshwater dive." It's no exaggeration. Over the years, thousands of divers from around the world have marveled at Ginnie Springs' crystal-clear water and startling natural beauty. Jacques Cousteau, in fact, characterized Ginnie Spring as "visibility forever."
Certified scuba divers who are first-time visitors to Ginnie Springs will want to use at least two tanks to visit the four diveable springs on Ginnie's property: one at Ginnie Spring and one at the Devil Spring system. Depending on the time of year, you may even want to use a third tank to drift dive the Santa Fe River.
OR, IF WE WANTED TO MAKE THE DRIVE....
Tarpon Spring, aka Crystal Spring or King's Spring, is subaqueous and is located on the south side of Banana Island. It is reported to be one of the finest freshwater dive sites in the State owing to its excellent visibility, size, convenience of access, and potential for underwater photography. Tarpon Spring is about 65 ft deep and 200 ft in diameter. On calm days, or at low tide, it has a slight boil or "slick." An adjacent spring (to the east) is reported to have a more vigorous flow. Although lights are useful to look around, I prefer to swim to the end of the cavern without a light and look around as my eyes adjust. Swimming out is incredible as there are often hundreds of fish conjugated around the two exits.
American Legion Spring is beneath a diving board at a public beach on Hunter Spring Run, at the south edge of Crystal River. It is operated as a county park with free parking and access.
Gator Hole may also be known as Magnolia Spring or Crystal Spring. It is about 0.5 mi. S. of Crystal River. Gator Hole is reported to have had rock spires and an extensive cave system that collapsed about 1963.
Idiots Delight is a group of three vertical shafts at least 20 ft in depth. The largest is reported to be 5 ft in diameter. Idiots Delight is about 0.25 mi. SE. of Gator Hole and also on the east side of Kings Bay.
Three Sisters Springs, also known as Middle Springs, is a few hundred feet north of Idiots Delight. Shark Sink is on the west side of the Bay. It reportedly developed when its roof suddenly collapsed about 1905. Shark Sink is 45 to 48 ft deep.