Tec Diving

It’s hard to imagine a better place to use your tec diving skills or to extend your diving capabilities than Espiritu Santo — three historical wrecks and depths up to 70 metres on the SS President Coolidge provide the perfect diving and training ground for extended bottom times and deeper dives.

Aquamarine offers Nitrox, Trimix, twins, bands and a range of courses to help you take your diving to the next level. We’re also rebreather friendly! Tec courses include:

TDI Basic Nitrox


This course teaches the basics of diving with enriched air, explaining the benefits as well as the limitations of breathing higher concentrations of oxygen while diving. You learn about air mixes up to 40% (levels used for recreational diving) and how to analyze Nitrox to prepare for your dives.

  • Length: ½ to 1 day, no dives
  • Prerequisite: Open Water Diver

TDI Advanced Nitrox


This course teaches the benefits, hazards and proper procedures for using Nitrox mixes up to 100% (oxygen). You will learn how to safely use these higher mixes as well as how to change gases for dives which do not require decompression.

  • Length: 2–3 days with 4 dives
  • Prerequisite: TDI or equivalent Nitrox certification, 25 logged dives

TDI Decompression Procedures

This course examines the theory, methods and procedures of planned stage decompression diving — which requires longer and deeper safety stops as you exceed recreational dive limits. Topics covered include the use of nitrox mixtures to increase decompression efficiency and dive safety, gas volume management, equipment configuration, methods of regulating oxygen levels and effectively planning decompression dives to a maximum depth of 45 metres.

  • Length: 3–4 days with 4 dives
  • Prerequisite: Open Water Diver, 25 logged dives

TDI Advanced Nitrox and TDI Decompression Procedures

A popular option for divers, this course allows you to combine Advanced Nitrox and Decompression Procedures into a single course of only 6 dives.

  • Length: 4–5 days with 6 dives
  • Prerequisite: TDI or equivalent Nitrox certification, 25 logged dives

TDI Extended Range


This course will help you to literally “extend your range” — you will learn proper techniques for diving on air up to 55 metres and using Nitrox or Oxygen to accelerate your staged decompression. Topics include gas supply management and dive planning.

  • Length: 4–5 days with 6 dives
  • Prerequisite: Advanced Nitrox, Decompression Procedures, 100+ dives, 25 over 30 metres

TDI Entry Level Trimix

Breathing Trimix (a mix of helium, oxygen and nitrogen) allows you to dive deeper than you can safely dive on air. With the reduction of nitrogen in the breathing gas, you experience much less narcosis and can enjoy safer, more comfortable deep dives.

  • Length: 4–5 days with 4 dives
  • Prerequisite: Advanced Nitrox and Decompression Procedures, 100+ logged dives

TDI Advanced Trimix


This course builds on the students previous skills, knowledge and experience. Helium is incorporated in to the breathing mix to enable the diver to conduct dives requiring staged decompression for depths up to 100 metres.

  • Length: 4–5 days with 4 dives
  • Prerequisite: Extended Range or Entry Level Trimix, 100+ logged dives, 25 over 30 metres

TDI Nitrox Gas Blender

This course teaches how to mix Nitrox for recreational diving. Topics include the correct use of oxygen, methods to produce various Nitrox mixtures as well as service and maintenance of the mix-system.

  • Length: 1–2 days, no dives
  • Prerequisite: none

TDI Advanced Gas Blender


This course teaches how to produce high quality gas mixtures for tec diving using helium and Nitrox. All relevant details related to blending gases are covered.

  • Length: 1–2 days, no dives
  • Prerequisite: TDI Nitrox Gasblender

TDI Instructor Training

Aquamarine offers Instructor Training for Nitrox, Advanced Nitrox and Decompression Procedures. Contact us to learn more about our instructor training and our course schedules.