In the winter you're going to be prohibited from diving the spring due to the presence of protected marine mammals (manatees). In the summer, this is a fun dive, but only for a couple of times. The water is consistently 72 degrees and clear as gin. You have to show your certification card to get in with dive gear, and a proper cave cert to carry any dive lights. If you're not into the marine spelunking thing then your dive is going to stop around 60', but you'll have some fun playing in the current. It's like underwater skydiving - you can lie on one of the shelves to rest and then pop out into the current and "skydive." Of course, there's not much to see, the opening feeding the spring drops down to 150' and then goes into a cavern system, but if you're not trained don't head down that way and kill yourself! People have died here - don't let yourself become the next!