Another Perdix 2 issue with 2 tanks

[andrew.tr...@gmail.com]

I did a dive today with 2 tanks: a 12.2L with air and a 5L with 31% using my Shearwater Perdix 2.

I started the dive on the 12.2L with air and 100bar I switched to the 5L. I did the gas switches with the Perdix 2. I loaded the data into both Shearwater Cloud and Subsurface Mobile 6.0.5504 on iOS.

Everything looks correct in Shearwater Cloud:

But in Subsurface it has the tanks around the wrong way and the graph does not show the tanks pressures correctly.

The graph is correct from a gas mix perspective but the table has the wrong mix for the tank. If I change the mix, it is even worse.

I realise that neither the Perdix nor Subsurface necessarily aligns transmitters to mixes but as I switched gases, Shearwater was able to work it out but Subsurface could not.

What am I missing? What do I need to change.

By the, on Wednesday I did a dive with 2 x 10.5L tanks, one with air and one with 31% and Subsurface got it correct.

Thanks,

Andrew.

[Michael Keller]

Hi Andrew.

On 21/6/26 18:12, andrew.tr...@gmail.com wrote:

The graph is correct from a gas mix perspective but the table has the wrong mix for the tank. If I change the mix, it is even worse.

Yeah, this will likely completely break how the gasmixes are shown in your dive profile. You are essentially telling Subsurface that you had configured the gasmixes incorrectly on your dive computer before you started the dive. Don't do that.

Instead you should fix the incorrect tank sensor assignment in the 'Sensors' column of the 'Cylinders' list:

I realise that neither the Perdix nor Subsurface necessarily aligns transmitters to mixes but as I switched gases, Shearwater was able to work it out but Subsurface could not.

You are correct, they are two completely distinct lists when they are transmitted by the dive computer. The Shearwater app likely makes guesses about what might be the correct assignment based on which tank shows a drop in pressure at what time in the dive.

Ngā mihi

  Michael Keller

[Andrew Trevor-Jones]

Thanks for the quick reply, Michael!

I wasn't even aware there was a 'Sensors' column.

That has fixed it (although the sensor numbers a not right with respect to the dive computer but that's fine).

Thanks again!

On 21 Jun 2026, at 4:46 PM, Michael Keller <mike...@042.ch> wrote:

Hi Andrew.

On 21/6/26 18:12, andrew.tr...@gmail.com wrote:

The graph is correct from a gas mix perspective but the table has the wrong mix for the tank. If I change the mix, it is even worse.

Yeah, this will likely completely break how the gasmixes are shown in your dive profile. You are essentially telling Subsurface that you had configured the gasmixes incorrectly on your dive computer before you started the dive. Don't do that.

Instead you should fix the incorrect tank sensor assignment in the 'Sensors' column of the 'Cylinders' list:

<WD5CxFvAgNoAFIQt.png>

I realise that neither the Perdix nor Subsurface necessarily aligns transmitters to mixes but as I switched gases, Shearwater was able to work it out but Subsurface could not.

You are correct, they are two completely distinct lists when they are transmitted by the dive computer. The Shearwater app likely makes guesses about what might be the correct assignment based on which tank shows a drop in pressure at what time in the dive.

Ngā mihi

  Michael Keller

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