Ditto the regret at your Crystal River [CR] experience. I went there one time, in February 2005, and it was wonderful. I plan to go again tomorrow, with a group. Last time, we rented a pontoon boat and it was great [no cigarette butts on the deck!]. I don't remember the name of the operator, but it seemed to be associated with a motel.
We first went to King Spring and it was fine to see the little manatee statue and dive to the spring outlet. Manatees had been there, as reported by some snorklers there, but we didn't see any. It was a worthwhile stop, though, with maybe 20 ft. vis.
Here is a shot from down at the spring entrance there:
But then we went to Three Sisters, and that was really great! It was a bit of an adventure, but lots of fun, for this ol' fella going against the stream that flowed into the river, in very shallow water with scuba gear on, but it was itself a great experience. But once in there, I can't express how splendid it was! Grear vis and manatees all about, resting [don't disturb!] and swimming about, solo and in pairs.
I also swam the margins, looking at fish in the tree roots, etc., and it was just crystal clear!
So, I guess it all depends on time of day, luck of the draw, etc.
PS: this is my first post with pics, and my first gallery creation on here>> thanks to the folks in the photo forum and here for the encouragement>> more later!?