You said that you asked the crew to tell everyone to "not grab the coral", but did you let them know that this specific guy was doing it. Most dive crews are very protective of their dive environment since their livelihood depends on it.
Also, you said he "came up with a very low amout of pressure in his tank (to the point of damage to the cylinder...". it's true the dive shops don't like you to empty the tank. But there is no "point of damage to the cylinder" unless you can breathe the cylinder down to such a massive negative pressure that it colapses.
Generally, if you have a dolt onboard, you should just keep your distance from him/her. If you observe dangerous behavior, mention it (quietly) to the crew. It is their responsibility to control the group. When you talk to the crew, be specific about what you saw. Don't expect them to berate the offender in front of everyone. Just because you don't see them scolding the offender doesn't mean they didn't. Most professional dive leaders will talk to problem-divers privately.
In fact, I'd have some reservations about a dive leader that berates a customer in front of other customers.
If you insist on approaching another diver about their behavior, again, you should do so privately. If you do anything to make them lose face in public, it just escalates their need to be defiant. Try not to be accusatory. Don't just say "Hey! Don't do that!". You should approach it in a more constructive way. "By the way, did you know those sea fans are soft corals and the slightest touch can make them die?" or "Say, have you ever heard of the one finger approach? If you need to steady yourself on the reef, find as bare a patch of rock as you can find and plant a single finger in the spot to slow your movement."
Also, you said he "came up with a very low amout of pressure in his tank (to the point of damage to the cylinder...". it's true the dive shops don't like you to empty the tank. But there is no "point of damage to the cylinder" unless you can breathe the cylinder down to such a massive negative pressure that it colapses.
Generally, if you have a dolt onboard, you should just keep your distance from him/her. If you observe dangerous behavior, mention it (quietly) to the crew. It is their responsibility to control the group. When you talk to the crew, be specific about what you saw. Don't expect them to berate the offender in front of everyone. Just because you don't see them scolding the offender doesn't mean they didn't. Most professional dive leaders will talk to problem-divers privately.
In fact, I'd have some reservations about a dive leader that berates a customer in front of other customers.
If you insist on approaching another diver about their behavior, again, you should do so privately. If you do anything to make them lose face in public, it just escalates their need to be defiant. Try not to be accusatory. Don't just say "Hey! Don't do that!". You should approach it in a more constructive way. "By the way, did you know those sea fans are soft corals and the slightest touch can make them die?" or "Say, have you ever heard of the one finger approach? If you need to steady yourself on the reef, find as bare a patch of rock as you can find and plant a single finger in the spot to slow your movement."
