The Gas Mixes section holds one Breathing Rates card, then one card per gas, then an Add Gas Mix button. The physics behind each figure is in Depth limits.
21/35
PrimaryTMX 21/35O₂21%He35%N₂44%
Open circuit
ppO₂ ≤1.40 bar
Max depth45 m
ppO₂—
Density—
EAD—
Reading a gas card
Four bands:
- The role, in small capitals above the mix name, with the cylinder configuration appended: Deco Gas · Stage. The edit, blend and remove controls sit beside it, and a Primary chip marks the gas breathed from the surface.
- The composition: O₂, He and N₂ as percentages.
- The derived figures: MOD, ppO₂, EAD and Density, plus a switch or drop depth where the gas has one. All are evaluated at one depth, named at the end of the row as @ 45 m.
- The cylinder: Tank, Fill and Capacity, and, once the plan is computed, how much you used and what is left.
A gas that breaches a limit there carries the warning on the card itself. See Warnings.
Adding a gas
Add Gas Mix opens a five-step dialogue. Mixes and roles walks all five.
The roles
Which roles a gas may take depends on the breathing mode. Mixes and roles lists all six and the oxygen ceiling each carries.
Watch for:
- An open-circuit plan needs a Bottom Gas, and a rebreather plan an Onboard Diluent, or the Plan step will not advance. See Warnings.
- Changing the breathing mode does not rewrite existing roles, so a plan switched to CCR reads as having no diluent.
Next
Cylinder configurations is the first thing the builder asks for, and the setting the rest of the gas follows from.