When nitrox burst onto the diving community in the early 1990s, it was considered a technical course promoted by the diving cowboys at these strange IANTD, TDI and ANDI certification agencies.

Whilst nitrox dive computers were available back then, it was the equivalent of purchasing the first car phone, flat screen television or laptop computer. Compared to today’s technology, they were expensive and lacking functionality. To be an early adapter, you had better ensure you had a good credit rating and deep pockets. Back then, I had graduated from dive tables to a dive computer – an air computer. Nowadays, all dive computers allow nitrox use as standard.

It was like owning an old mobile phone that are now referred to as bricks. The new dive computers are compared to a smartphone; indeed, the new OLED screen technology is adapted from smartphones. Needless to say, when diving nitrox, my air diver computer was left back at the dive centre and a depth gauge and dive accompanied my dive slate with a full hand calculated dive plan neatly written out complete with turn-points, CNS%, OTUs and gas usage for each depth in runtime.

Geez, I wasn’t even going into deco, this was just a three-level dive with standard scuba equipment. After a while I started to get smart and kept copies of old dive plans so I could redive certain profiles without the need to recalculate the whole dive. What you gained from exposure to these calculations and dive planning is a through knowledge of nitrox whilst you developed the discipline to execute your dive plan to the exact depth and time.

My plans were always to the no-decompression limits for each depth on a multi-level dive, you had to display personal discipline, a trait I maintain to this day even though I have graduated to a dive computer. Even with current risk adverse dive computer profiles, they still allow more bottom time than the old tables and multilevel profiles.