The best hard coral in Hong Kong - Tung Ping Chau 東平洲

I heard for a long time that Tung Ping Chau has an abundance hard coral near its pier.
Tung Ping Chau is one of the most remote diving sites in Hong Kong. It is not often that the diving operators in Hong Kong offer this diving site.

On 17th September, I dove there. We took one and half hour to travel there from Wu Kai Sha Pier. I planned to have three dives on that day. Before I entered to sea, the captain showed a map, which has an area marked as special region. Then I went there first to explore what special it was. This area is a sandy bottom with some sea anemones and clown fishes. I don't understand what the meaning of special is.
Then I stuck into my original target in second dive. When I saw the area of hard coral garden, I have rated that it is the best hard coral living area in Hong Kong. Many different hard coral species and even families grow together in very heathy condition and cover a large area. I was very enjoyable of this dive and didn't want to return.
When I have surfaced, they yelled me to return the boat at once. I wondered whether an accident happened. I asked them what happened to yell me. They said that they would change dive site because this dive site had nothing.
Oh my god, it was because they went to a wrong area. I told them I saw the most beautiful hard coral area in Hong Kong, but it was too late. The boat was starting to travel and leaving Tung Ping Chau.
I was very angry that they even didn't do a little bit research about the dive site.
I was the only one who saw the beautiful hard coral.

I found that it was a so call instructor's suggestion.
We travelled in such long distance and time because of its beautiful hard coral. All this effort was wiped out by such a no sense hopeless instructor.

Platygyra carnosus

Favites pentagon

How much pressure will remain in tank when you can't breath from your regulator?當氣瓶沒氣時。

If you still remember what you have learned from your diving course, the intermediate pressure of the first stage is about 10bar. It means that a balance type first stage will supply 10 bar to second stage no matter how much air remains in the tank.
Will first stage supply air when tank pressure below 10 bar?
The answer is yes.
When tank pressure is below 10 bar, the piston will open freely.
At a result, the tank can be drawn to 0 bar.