One other thing in open water you do have the option of surfacing, even with consequenses. Overhead is a different story and that option is gone and you can't afford to loose ANY gas that could be saved with an isolator.
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include