How to achieve stable gas layers

[Medalla]

This is something that has been on my mind after starting a new run last week. Is there a way to calculate how much gas is needed of each for 2 (or more) gases to form a stable (meaning no bouncing around or tiles changing gas pressure) layer? It seems like the logical step is to keep adding more gas to the top layer, but i want to know if there's a way to calculate the ratio rather than brute forcing it (with debatable results?)

[Tigin]

Stability is predominantly based on the fact that it was stable before. As long as the stable layer gas in question doesn't have significantly more mass than the gas below/above it, it won't ever bounce around.

To achieve a stable layer to begin with, it's easiest to pump in small amounts of the stable layer gas first and let it disperse. When you add the second layer in, it'll compress the first gas to a stable layer.

[Crapgame]

On 1/30/2026 at 11:59 AM, Tigin said:

Stability is predominantly based on the fact that it was stable before.

I just was experimenting with a build that included stacked gasses and I would say it is fair to say "predominantly", but there sure are some weird quirks to it. 

I sandboxed in a uniform layer of CO2 @ 1kg/tile and then sandboxed in hydrogen @1.5kg tile. It was stable for a little while but then small (<100g) blobs of CO2  started appearing above the CO2 layer. Also the CO2 layer started varying from tile to tile across the room. None of the CO2 ever went past that 2nd lowest tile, but it was annoying that the layer would not just stay put at the very bottom layer like it began. 

 

[KittenIsAGeek]

OK, so.. stacked gas layers are inherently unstable unless there's nowhere for them to move.  For example, this little pocket of hydrogen and CO2 will never be stable.

Spoiler

If I mouse around, some of the hydrogen is around 100g, some is around 1200g, one CO2 packet is 1042g and the other is 4031g.  Theoretically there's enough CO2 for the 5 lowest grids to be at around 1000g and enough hydrogen to stabilize the top 4 grids at around the same pressure.  However, this won't ever happen because the CO2 wants to sink into that lowest grid spot, but has too much pressure to stay there.

Spoiler

In this fine example of hydrogen, oxygen, and CO2, it will always be stable (unless another gas comes in) because none of the gasses have anywhere they want to move.  The CO2 is already at the lowest spots, the hydrogen is at the highest spots, and the oxygen isn't going to displace the hydrogen or CO2 unless there's a large pressure differential.  In this case, all the pressures are in the same ballpark, so that won't happen.

Spoiler

This room is pseudo-stable.  Unless the pressure drops really low, the top bar of hydrogen will always be there, so the gas pump can never pull in oxygen.  I've tested it at 200g hydrogen, 1800g oxygen.  However, it isn't completely stable.  Sometimes the hydrogen produced by the electrolyzers will drop down instead of up and get caught by the oxygen pumps, especially when oxygen pressures are low -- even when hydrogen pressures are also low.  On the other hand, the bottom row of oxygen will never swap with hydrogen even if hydrogen is 1800g and oxygen is 200g.

 

[Frustrated]

This sorta just "happened" to me while I was trying to pull a bit of chlorine out of the bottom of the ranch.

 

Spoiler

I doubt anything is going to change it unless I break a wall.

[KittenIsAGeek]

On 2/22/2026 at 10:48 AM, Frustrated said:

This sorta just "happened" to me while I was trying to pull a bit of chlorine out of the bottom of the ranch.

Yikes.  Yeah.  Unless you can get a stable layer of chlorine all in one shot, then the interface between the chlorine and hydrogen will be unstable and you'll have areas of high and low pressure.  The low pressure will let polluted dirt off-gas and if the chlorine doesn't have another cell of chlorine to escape into, it will get destroyed.  That will leave you with polluted oxygen and hydrogen.

[Frustrated]

To be clear, that's exactly what I wanted.  Drecko Ranch, so, I'm trying to make as much of it Hydrogen gas as possible, while still keeping at least one layer of O2, pO2, or CO2 for the Mealwood (Glossy Dreckos).  It just happened to work out really well.  "Stable layers" tend to happen with certain pairings (Hydrogen and almost anything else, for example) automatically and not at all with others (O2 and pO2, CO2 and Cl2).

[Bzhydack]

On 2/24/2026 at 10:16 PM, Frustrated said:

To be clear, that's exactly what I wanted.  Drecko Ranch, so, I'm trying to make as much of it Hydrogen gas as possible, while still keeping at least one layer of O2, pO2, or CO2 for the Mealwood (Glossy Dreckos).  It just happened to work out really well.  "Stable layers" tend to happen with certain pairings (Hydrogen and almost anything else, for example) automatically and not at all with others (O2 and pO2, CO2 and Cl2).

Its beause of density difference. Hydrogen is the lightest gas, so its always rising up. Oxygen and Polluted Oxygen has the same density - they mix together or form few layers on their own (what is very annoing). Also, you should be able to form stable layer with CO2 too, as its the heaviest gas, its even heavier than Steam - but due to many sources CO2 can have many vertical turbulences.

[Frustrated]

Mhm.  That was the plan all along.  I only needed a layer or two of pO2/O2/CO2 for the mealwood, the rest had to be H2.  It just happens naturally.