CCR Diluent error message

[Thomas JACOB]

Hi all,

I’m trying to figure out how to clear an error message for one specific dive downloaded from a  monitor Shearwater Petrel 2 (not controller only for this dive).

The message is:

“Dive 470, dive computer: Shearwater Petrel 2: CCR dive, but no diluent cylinder found. Please add or select the correct cylinder use.”

I have never recorded any cylinders, neither in OC mode nor in CCR mode, so I can’t find where to add or modify this information for that dive.

Thanks in advance for your help.

[Michael Keller]

Hi Thomas.

As the message states, this means that the dive has a dive type of 'CCR', but in the cylinder list in the Eqiuipment tab none of the cylinders (that were downloaded from the dive computer when importing the dive) has got 'diluent' set as the Use.

To my knowledge this should not happen for recent versions of Subsurface and for recent versions of firmware running on Shearwater computers. So I am wondering:

- what version of Sunsurface are you running

- on what operating system

- what's the firmware version on your Shearwater dive computer

Also, if you don't mind, can you please share the unmodified dive log for this dive (create new logbook, download your dives from this dive computer into it)?

Ngā mihi

  Michael Keller

[Thomas JACOB]

Hello Michael

I reinstalled Subsurface this afternoon, keeping and reusing my existing logbook, so I believe this is the latest available version (windows).

I’ve just discovered how to change tank usage in the Equipment tab. However, all my CCR dives that follow one another still show the same issue, which I can only fix one dive at a time. This issue affects all dives downloaded from Shearwater units over several years, indicating that multiple firmware versions are impacted.

 
Before today’s reinstallation, I never encountered this problem—I didn’t even know it was possible to change tank usage for dives downloaded from my Shearwater! 

Regards

Thomas

[Dirk Hohndel]

On Jan 18, 2026, at 11:45, Thomas JACOB wrote:

Hello Michael

I reinstalled Subsurface this afternoon, keeping and reusing my existing logbook, so I believe this is the latest available version (windows).

I know this sounds silly... but it always helps us to actually know WHICH version you are running. It's in the About dialog. It's really not that hard.

/D

[Michael Keller]

Hi Thomas.

On Mon, 19 Jan 2026 at 09:09, Thomas JACOB <opi...@gmail.com> wrote:

I reinstalled Subsurface this afternoon, keeping and reusing my existing logbook, so I believe this is the latest available version (windows).

I’ve just discovered how to change tank usage in the Equipment tab. However, all my CCR dives that follow one another still show the same issue, which I can only fix one dive at a time. This issue affects all dives downloaded from Shearwater units over several years, indicating that multiple firmware versions are impacted.

 
Before today’s reinstallation, I never encountered this problem—I didn’t even know it was possible to change tank usage for dives downloaded from my Shearwater! 

Yes, older version of Subsurface did not set the correct cylinder use for CCR dives, which then resulted in the decompression information calculated by Subsurface being incorrect for some CCR dives.

Newer versions (newer than about 1.5 years old) do this correctly, but unfortunately there is no way to retroactively add this information for dives that were imported with an older version, as the information on which cylinder was used for what was discarded during the import.

You can manually fix this, or you can re-import the dives from your dive computer (and then delete the 'old' dive computer from each dive).

Ngā mihi

  Michael Keller

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