A question with a number in it comes back as a card, and the card is the calculation, laid out the way the app lays the same figures out elsewhere. The Gas Blender page opens on these three: “Gas blender ready. Give me a gas mix and depth to analyse, ask what to use at a target depth, or describe a fill.”
A mix at a depth
“What is 21/35 like at 45 m?”
- ppO₂: the oxygen partial pressure at that depth.
- MOD: the depth at which the mix reaches the ppO₂ ceiling.
- EAD: the air depth carrying the same narcotic load.
- Density: the gas density there, against the 5.2 g/L figure.
Every warning the app raises on that mix is on the card. Tunang treats 1.6 bar as a decompression maximum rather than a working target, and never certifies a gas: a mix is not acceptable merely because it sits under a mathematical maximum. One that analyses cleanly at 70 m may still be the wrong gas for the dive that goes there.
The best mix for a depth
“Best mix for 60 m, narcosis no worse than 30 m?”
Oxygen rises to the ppO₂ limit at the target depth, then helium until the equivalent air depth sits at or below your narcosis limit, then further if density needs holding at or below 5.2 g/L. Oxygen rounds down, and the removed oxygen goes into helium. The card says when density was the binding constraint, because helium added for density is a different decision from helium added for narcosis.
A switch it will not pass
“Can I switch from 18/45 to EAN50 at 21 m?”
Every counterdiffusion test the switch fails is named with its limit. Asked instead what to switch to, Tunang looks for the gas with the smallest nitrogen increase that passes all of them, and says plainly when there is none.
A fill comes back as numbered steps, oxygen then helium then air, each with the pressure it adds. A blend is never a verified fill: it is only as trustworthy as its analysis, the blending method and the cylinder, and Tunang is required to say that a gas “needs to be verified by analysis before use”.
Next
- Best mix and ICD violations are the same calculations as forms.
- Tunang in the planner works on the dive you have open.