Getting started¶
This page walks you through building your first dive plan in AeroPlus Deco — from a blank app to a complete runtime schedule.
Open the app¶
Visit sjjan.github.io/aeroplus-deco in any modern browser. Nothing to install yet — the app runs entirely in the browser.
The first time you open it, you'll see an empty Plan 1 with the default settings: open-circuit mode, ZHL-16C-GF, GF 50/75, fresh water, sea level, metric units.
Working in feet and psi?
Switch Settings → Units to imperial before you start and every field below will ask for imperial values instead. See Units.
Install as a home-screen app
Once you're using AeroPlus Deco regularly, install it to your phone or laptop so it opens like a native app and works offline. See Install as app.
Build a quick plan¶
We'll plan a typical recreational tech dive: 40 m for 20 minutes, on air with 50 % nitrox for deco.
Step 1 — Add your bottom gas¶
In the Gas & cylinders card, tap + Add. The cylinder modal opens with Bottom gas selected. Enter:
| Field | Value |
|---|---|
| O₂ % | 21 |
| He % | 0 |
| Size (ℓ) | 12.0 |
| Fill (bar) | 200 |
Tap Save cylinder. Air (21/0) is now your bottom gas.
Step 2 — Add your deco gas¶
Tap + Add again. This time, select Deco gas at the top, then:
| Field | Value |
|---|---|
| O₂ % | 50 |
| He % | 0 |
| Size (ℓ) | 11.1 |
| Fill (bar) | 232 |
Tap Save cylinder. The deco gas appears in the list with a checked box — it will be used automatically when the algorithm reaches its MOD on ascent.
Step 3 — Add a dive segment¶
In the Dive profile card, tap + Add. Enter:
| Field | Value |
|---|---|
| Depth (m) | 40 |
| Bottom time (min) | 20 |
The Gas dropdown will already have your bottom gas selected. Tap Save segment.
Step 4 — Calculate¶
Tap the big blue Calculate dive plan button.
In a fraction of a second, the Deco plan card appears with:
- A dive profile chart showing depth, GF ceiling, and average depth over time
- A GF99 chart showing tissue saturation through ascent
- A runtime schedule listing every depth-time-gas combination
- A gas plan showing per-cylinder usage and rock-bottom reserves
- CNS / OTU oxygen-exposure totals
- Any warnings at the top (e.g. gas density, gas shortfall)
Reading the output at a glance¶
Three numbers tell you the most about the dive at a glance:
- Total deco time — sum of all stop durations
- TTS at ascent start — how long it'll take to surface from the deepest point
- Deepest ceiling — the deepest depth your tissues will tolerate (the first GF Low stop)
For a full walkthrough of every card and chart, see Reading the output.
What to do next¶
- Tune your gradient factors. Defaults are conservative. Read Gradient factors and consider the Andy Davis method for setting GF Low on OC.
- Plan a multi-level dive. Add more segments below the first — each can be at a different depth. See Dive profile.
- Save a contingency plan. Toggle Deeper +3 m and Longer +3 min to see how the deco changes if you go over.
- Share with a buddy. Use the share menu to send a link your buddy can open in any browser without installing anything. See Sharing & backup.
Cross-check, every time
No matter how clean a plan looks in the app, always verify it against a second source — another planning tool, a dive computer simulator, or your instructor. Decompression involves real risk and a single off-by-one in your gas mix or depth entry can move the plan into dangerous territory.