That is the cavern inkdiver is refering to. He is absolutely correct in that it is a cavern not a cave but I understand how someone without the training would consider it to be a cave. Just dive within your limits of comfort and training. Don't let anyone push you into something that will harm you. When and if you decide to get trained to take on such an environment it is a nice dive. Then some of the differences between cavern and cave will matter to you.
