Gas Presets

What it is

A gas preset is a named combination of a breathing gas and a cylinder that you save once and reuse everywhere. Instead of typing the O₂ %, He %, cylinder volume, and working pressure into every tool each time, you save your usual setups (your AL80 of air, your EANx32 deco bottle, your trimix back gas) and pull them in with a tap. The name is just a label you choose. A preset stores the gas mix and cylinder, not a role like stage or bottom gas.

You manage presets in Settings → Gas Presets. Gas Presets is a top-level row on the Settings screen, and its card reads “Manage saved gas & cylinder presets.”

What a preset holds

Each preset stores a gas mix and the cylinder it lives in:

Field	Meaning	Notes
Preset Name	Your label for it	For example “EANx32 deco bottle” or “Back gas Tx18/45”
Gas (O₂ %)	Oxygen fraction	21 % is air
He %	Helium fraction	0 % for air or nitrox; set it for trimix
Volume	Cylinder water capacity	In your volume unit (litres or cubic feet)
Pressure	Cylinder working pressure	In your pressure unit (bar or psi)
Configuration	Single or Twinset	Twinset means doubles (two matched cylinders)

The Configuration toggle switches between Single and Twinset (doubles). Set it to Twinset and the preset counts two matched cylinders: the free gas volume doubles, and the preset shows an “x2” tag in the editor and in the picker. Use Single for one cylinder, including each side of a sidemount pair you handle separately.

The Volume field is the cylinder’s water capacity, not the free gas it holds. An imperial “AL80” name describes roughly 80 ft³ of free gas at working pressure, but its water capacity is about 11 L. In metric, the form shows the resulting free gas volume below the fields so you can sanity-check the numbers; in imperial it shows the derived water volume instead, since the capacity figure is the one you typed. You can also tap Pick from common cylinders to choose a known cylinder (AL80, LP95, HP100, and others) from the cylinder database, which fills the volume and working pressure for you.

Built-in presets

Dive Kit ships with two starter presets so the feature works out of the box:

• Air (AL80) is a single AL80 of air.
• Air AL80 Sidemount is a twinset of two AL80s of air, set as the default.

Both built-ins behave exactly like presets you create. You can edit them, rename them, or delete them. The names are unit-neutral, so they read sensibly whether you use metric or imperial.

Create, edit, and delete a preset

Where presets are reused

Once saved, a preset is available in every tool that takes a gas and cylinder. Open a gas input, tap the preset button, and pick a preset to fill the gas mix and cylinder fields. The tools that use it:

• Deco Planner
• Gas Blender
• Gas Usage planner
• Mix Result
• SAC/SRMV, where it fills the cylinder you breathed from in the measurement you are adding

The button label and behaviour differ slightly by tool:

• In Gas Blender, Gas Usage, Mix Result, and the SRMV/SAC calculator the button is labelled Quick Fill and it overwrites the gas and cylinder fields you are editing.
• In the Deco Planner the button is labelled Add from Preset and it adds the preset as a new gas to your gas list instead of overwriting a field.

The picker also has a Pick from common cylinders button below the preset list. It fills the fields from any catalogued cylinder (AL80, LP95, and others) as 21 % air, without saving a preset. Use it for a one-off cylinder you have not saved.

If you delete all of your presets, the button stays where it is. The sheet then opens as Pick a Cylinder, on a line telling you nothing is saved yet, with Pick from common cylinders below it, so you can still fill a cylinder in one tap while your preset list is empty.

Behaviour and limits

• Presets are stored on your device and need no account or connection. See Offline use.
• A preset is a convenience for entering numbers. It does not verify your real cylinder fill or gas analysis. Always confirm the actual mix and pressure before you dive.