Wazzup Pilipinas!
Five days exploring the diving sites of Bohol seems like a long time already. But with a few unavoidable limitations for both body and equipment (plus the fact that there's a lot more equally popular places to see within Bohol), we can only go underwater at a particular length of time.
Both the local and foreign dive experts/photojournalists from different countries explained that the oxygen tank being used in our diving tour can last roughly an hour depending on the diver. They say men consume more air since they have bigger lungs than women. Also, professional divers who are already familiar in breathing properly underwater would be able to conserve their air to last them longer. Newbies usually breathe in air faster since they would sometimes panic.
The depth of the dive site and the movement of water current are also considerations since you will tend to consume more air if any of the situations are present. Basically, the more you move around underwater and the more effort you exert in swimming will determine how long your air last.
This is why you have to regularly check on your equipment to see if you still have enough air with you. The problem with underwater photography, we tend to be enthralled with the awesome beauty of the marine life that we would sometimes be tempted to go further down under or stay underwater longer.
Thus, dive buddies like divemasters are recommended to be there to keep you safe and reminded of the limitations. You will understand what I mean once you go down under and experience the beauty surrounding you. The marine life is so stunning that you'll be amazed of how diverse the creatures we can find under the depths of the sea.