The TDI Inspiration and Evolution Mixed Gas course (certification depends on unit/electronics used) is your next step into closed circuit rebreather diving and with the addition of helium as a diluent gas, it is your opportunity to explore a little deeper.


Using the latest in technology CCR's maximise your gas supply and provide the optimum breathing gas for any depth by maintaining a constant partial pressure of oxygen (PPO2). During the dives (minimum of six) your TDI Instructor will teach you all the nesscery skills to conduct CCR dives utilising helium as a diluent gas and oxygen levels as low as 16 percent to a maximum depth of 60 m .


The skills include:

  • Calculating off-board gas requirements
  • Recovering from system failure
  • Calibration of electronics
  • Emergency procedures
  • Removing and replacing off-board gases
  • Surface marker buoy deployment


The TDI Inspiration/Evolution manual provides comprehensive information about the units and how they operate during a dive, this combined with the TDI Trimix Diver manual complete the academic knowledge needed to conduct mixed gas CCR. Also available is the Inspiration/Evolution build-up check list that can be adhered to the unit case for easy reference.



  • Minimum logged dives: 50 rebreather hours distributed over a minimum of 50 dives on the specific rebreather. 50 % deeper than 20m. All to be deeper than 9m. If the diver has 50 hours on another CCR unit recognized by TDI, only 25 hours are required to be on the Inspiration / Evolution.
  • Have completed and qualified the TDI Air Diluent Rebreather Course or equivalent from agencies recognized by TDI.
  • Minimum age: 18 years old


Download the full TDI Course Outline as PDF Document


course duration: 5 days