Feature request: GF 0/0 & compartment pressure values.

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Ryan Holden

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Jan 6, 2026, 3:21:03 AM (10 days ago) Jan 6
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Hello,

Would it be possible to request a couple of new features?

1 - This is actually currently a bug in my version, but it's proving quite useful. When I open the dive planner, the GF is set to 10/0 (and is actually calculating the dive profile to this too), despite showing 10/40 in the config window. This is actually quite useful for me as I try to wash as much inert gas out as possible before exiting the water, and I also avoid GF99 registering anything at all on the ascent. Would it be possible to allow GF Low and GF Hi to be set as low as 0, at least within the dive planner? Currently I think the lowest is 10/40. On a side note, when I change the values in the GF box they then update in the dive profile window respectively. 
Screenshot 2026-01-06 160747.png

2 - I'd like to use the dive planner to understand how long it takes for each tissue compartment's Pn2 saturation to reach 0.79 bar, which would be the same as at the surface. Currently we have a tissue heat map, but it doesn't give an indication of tissue saturation pressure values, only a colour relative to the current calculation from pressure / gas mix and resulting on gassing or off gassing. The closest thing I have found so far is within Diving Log 6.0, where we have a tissues bar chart (see below) that gives real time calculations as you scroll through the dive profile timeline, however, it does not offer any numerical values, so you have to try and guess when tissues are at 0.79. A small numerical value at the top of each bar would be awesome.
Screenshot 2026-01-06 161913.png

Happy to have a discussion, I suspect #1 is fairly straight forward, but #2 might need a little work, in terms of the GUI.

Michael Keller

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Jan 6, 2026, 5:50:32 PM (9 days ago) Jan 6
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Hi Ryan.


On 06/01/2026 21:21, Ryan Holden wrote:
> Would it be possible to request a couple of new features?
>
> 1 - This is actually currently a bug in my version, but it's proving
> quite useful. When I open the dive planner, the GF is set to 10/0 (and
> is actually calculating the dive profile to this too), despite showing
> 10/40 in the config window. This is actually quite useful for me as I
> try to wash as much inert gas out as possible before exiting the
> water, and I also avoid GF99 registering anything at all on the
> ascent. Would it be possible to allow GF Low and GF Hi to be set as
> low as 0, at least within the dive planner? Currently I think the
> lowest is 10/40. On a side note, when I change the values in the GF
> box they then update in the dive profile window respectively.


Yes, this looks like a bug, and is probably not what most users would
expect. But I am not able to reproduce this, what version of Subsurface
are you using and on what OS?


> 2 - I'd like to use the dive planner to understand how long it takes
> for each tissue compartment's Pn2 saturation to reach 0.79 bar, which
> would be the same as at the surface. Currently we have a tissue heat
> map, but it doesn't give an indication of tissue saturation pressure
> values, only a colour relative to the current calculation from
> pressure / gas mix and resulting on gassing or off gassing. The
> closest thing I have found so far is within Diving Log 6.0, where we
> have a tissues bar chart (see below) that gives real time calculations
> as you scroll through the dive profile timeline, however, it does not
> offer any numerical values, so you have to try and guess when tissues
> are at 0.79. A small numerical value at the top of each bar would be
> awesome.


I think this is a question best put to Robert Helling who has written
most of our decompression code.


Ngā mihi

  Michael Keller

Ryan Holden

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4:43 AM (11 hours ago) 4:43 AM
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Hi Michael,

I'm running Windows 11, with  Subsurface 6.0.5498-patch.1.pull-request.fixup-ccr-setpoint

Ryan

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Michael Keller

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5:02 AM (11 hours ago) 5:02 AM
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Hi Ryan.


On 15/01/2026 22:42, Ryan Holden wrote:
> I'm running Windows 11, with Subsurface
> 6.0.5498-patch.1.pull-request.fixup-ccr-setpoint


Can you please try with current
(https://subsurface-divelog.org/current-release/) or latest
(https://subsurface-divelog.org/latest-release/) and see if the bug
reproduces?


Ngā mihi

  Michael Keller

Ryan Holden

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5:19 AM (10 hours ago) 5:19 AM
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Hi Michael,

Whilst it might be a bug in the version I'm using, I'm not looking to have it resolved, I'm requesting to be able to set the GF values as low as 0/0 - currently the lowest available setting is 10/40. I've been exploiting the bug so far, but if I update to the newest version that does not have the bug, I would lose this "feature".

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