I think everyone is missing the point. Although it is called an Advanced Open Water Course the whole point of the cource isn't to all of a sudden become some sort of "advanced" diver. It is to advance an OW diver's skill levels and confidence to a level where they can explore and dive in new environments. To not teach an AOW course because someone doesn't have a Nitrox certification is nothing short of ludicrous. On my AOW we did a night dive, a deep dive (30m), a wreck dive, a naturalist dive, as well as a navigation dive. Once completed I just felt more confident in my abilities as a diver in these new conditions. Because I did a wreck dive as part of this course it didn't all of a sudden make me an "advanced wreck diver". Instead it opened the door that there was a wreck diving specialty course which I could take in order to further my knowledge and skills in this field. I have asked around to all the dive shops in the area, and not one requires a nitrox certificate for an Advanced Open Water course. Not only that, the Nitrox certification is not necessary for the Rescue Diver, Divemaster, AI, or Instructor Course either. As for PADI I've done all my training with them and have been happy doing so. Students are limited to two Open Water Dives a day, Instructors know thier limits and because of the shallowness of the water in which the training is done it is not uncommon to do three to four training dives in a day. With a nice surface interval of course. I'm new to the post so I hope I've added something useful to you all.