Course Overview
TDI Advanced Trimix is the top open-circuit TDI diver course for divers who want to use hypoxic trimix on very deep technical dives. The official TDI page describes training for depths as deep as 100 metres/330 feet using oxygen levels below 17 percent. At this level, the focus is exacting gas planning, multiple decompression or stage cylinders, decompression discipline, and clear decision making when the margin for error is small.
This course is intended for certified TDI Extended Range or Trimix Divers, or equivalent, who want to extend depth range and technical capability. TDI lists minimum age 18, the Extended Range or Trimix prerequisite, and proof of 100 logged dives, with 25 deeper than 30 metres/100 feet. Students should already have mature decompression procedures, strong team communication, and reliable technical equipment control.
Training covers hypoxic gas use, equivalent narcotic depth planning, helium and nitrogen absorption and elimination, CNS and OTU limits, isobaric counter diffusion, HPNS, decompression gases, contingency planning, gas switching, SMB or lift bag use, and emergency procedures. In High Springs, Florida, it is a capstone step for divers preparing for major deep projects. Successful students should leave with a sharper, more conservative framework for planning and executing advanced trimix dives.
