Oxygen is toxic under pressure. A lesson that stayed on my head since I took up a new diving certification last September. It is a fact highlighted during the course.

It is also a fact that the air we breath on land is composed of 21% oxygen and 79% nitrogen. In diving, the same proportion applies on compressed air. But studies and developments in scuba diving paved the way for breathing air on varying proportions, containing higher percentage of oxygen. This has proven to have advantages and of course risks.

So diving using Enriched Air Nitrox (EANx) was introduced. It means having a higher percentage of oxygen and lower nitrogen than the ordinary, which means decrease risks of decompression sickness (DCS) and nitrogen narcosis. But it doesn’t follow that diving with nitrox means one can dive deeper, although it allows divers to stay longer underwater at a given depth than the standard air limit without increasing the risk of having DCS. In fact, it decreases the risk of DCS for profiles that adhere to standard air tables. However, it greatly exposes divers to oxygen toxicity because of underwater pressure. Oxygen toxicity can cause death but avoidable and most casualties that suffer to this condition die not because of it but due to drowning.

So our Enriched Air Diving lesson went on. Together with Ate Claudia, our instructor was Sir Renoir of Mantangale Alibuag Dive Resort in Balingoan, Misamis Oriental. An instructional video was shown to us followed by short discussion on concepts of EANx diving, then Sir Renoir taught us how to setup our dive computers, analyze oxygen blend and air content, and fill up the tank log.

The real fun started as we went underwater. Aside from the enriched air nitrox we were breathing, the nitrox setup of our computers and the conscious efforts to not exceed the maximum given depth to avoid oxygen toxicity, everything appears to be as usual.

We dive in Banaug Shoal and Lapinig Island, both are near the resort.

Banaug Shoal, also known as Again Reef, is Mantangale’s house reef. A small coral area unbelievably populated densely by various marine species. It was voted as one of the best house reefs by Asia Diver Magazine and undoubtedly, the site is worthy of its distinction. Surgeonfish, Snappers, Groupers, Trumpetfis, Scorpionfish, Lionfish, Pigmies, Eels, Crinoid and other species take refuge in various species of corals and gorgonians of Banaug Shoal.

It was my second time to dive in this site but the place never ceases to amaze me. As if my first time, I was awed by the magnificent view around me. The resort dive guide was with us with some bait fish, and he fed the fishes while we were navigating the shoal.

We surfaced after 43 minutes of diving in nitrox with 32% blend of oxygen.

Dive Profile: Maximum Depth – 29.2 meters/Date-Time of Descend – 17-Sep-2011 1508H/Bottom Time – 43 minutes/Water Temp – 30°C/Start Air – 200 bars /End Air – 70 bars/Blend 32% O2

On our surface interval, we did air analysis once more before sailing towards our next dive site. Our final dive for the day – Lapinig Island.

Lapinig Island is the small islet you see near the port of Balingoan if you are going to Camiguin, just a short boat ride from Mantangale Alibuag Dive Resort. It has a sandy bottom with coral patches that attracts Snappers, Groupers, Mandarinfish and other small tropical fishes and macro species. The site also features an underwater spring locally called “alibuag“.

It was my first time to dive there, Ate Claudia’s second but I believe Sir Renoir stopped counting. There were stories of Manta sightings in Lapinig Island and I was hoping to see one, and though no Manta showed up, we still enjoyed the dive. There were too many stuff  that kept us busy as we dive in Lapinig Island that I forgot about the Manta.

Dive Profile: Maximum Depth – 27.1 meters/Date-Time of Descend – 17-Sep-2011 1642H/Bottom Time – 47 minutes/Water Temp – 30°C/Start Air – 200 bars /End Air – 60 bars/Blend 30% O2

It was almost dark when we surfaced, proud for completing our checkout dive for nitrox certification. To formalized our course, we took the written examination that night, and almost aced it 🙂

At last, we completed the course. It was a new milestone for Ate Claudia and I. It wasn’t actually a required course in recreational diving but it helps on some occasions. Now we can’t wait to use our newly acquired knowledge (and certification) on diving with nitrox.

Thanks you so much Sir Renoir and Sir Dodong of Mantangale Alibuag Dive Resort. Oh by the way, sorry for some quite technical scuba diving terms on this post 🙂