This is an interesting site, but pales in comparison to the nearby Devil's Den. If I had to choose between the two sites for a future dive, I'd pick the Den. Blue Grotto was my first spring dive and I found the experience interesting and the surroundings somewhat surreal. Much different than the ocean diving I normally do in Jupiter, WPB and the Keys. The afternoon light cascading through the top of the roof makes for interesting photographs. The water is fairly comfortable at 71-72 degrees, but a hood or beanie for your head is a must. My buddy and I saw all that we wanted to see of the cavern on one tank: actually, after 30 minutes or so (about 50% of the tank), we were looking for things to do. I don't think I'd dive Blue Grotto again, but I am glad I tried it.