I went to Tonga for New Year's 1999/2000 for 3 weeks. We dove everyday because my bro-in law had a Aussie buddy there who ran a dive shop and knew all the ultimate dive spots. When we were there the average visibility was 100-200 feet. It was unbelievable, I sure wish I had an underwater camera on that trip. Diving through this cave from one end of a small island to the other was the ultimate, also the scariest.