Best TrimixBest Trimix for depth
Best Trimix gas for selected depth and Equivalent Narcotic Depth, limited by maximum oxygen partial pressure.
Give Deep Tools your oxygen limit, maximum gas density, target depth and END, and it finds the mix that meets all of them with the least helium.
How it works
FO₂ = ppO₂ max ÷ (depth ÷ 10 + 1), rounded down · helium added in 1 % steps until END and density fit
- END oxygen counts as narcotic
- Density about 5.2 g/L is the commonly recommended maximum
Example
- Target
- 40 m, ppO₂ 1.4, END 30 m, max 5.2 g/L
- By END
- Tx 28/20 would be 5.43 g/L, too dense
- Best mix
- Tx 28/25 at 5.16 g/L
How it works
FO₂ = ppO₂ max ÷ (depth ÷ 32.8 + 1), rounded down · helium added in 1 % steps until END and density fit
- END oxygen counts as narcotic
- Density about 5.2 g/L is the commonly recommended maximum
Example
- Target
- 120 ft, ppO₂ 1.4, END 90 ft, max 5.2 g/L
- Oxygen
- 1.4 ÷ 4.66 = 0.30 → 30 %
- Best mix
- Tx 30/20 at 5.07 g/L
Take it to the dive site
The same calculator works offline in the Deep Tools app, together with the dive planner, dive log and blender.
