Bug: If using multiple cylinders contain same mix, only one cylinder is ever used.

[Rolf-Smit]

If more then one cylinder is used with the same mix, the gas plan will always only utilize one, even though one cylinder may not contain enough gas for the dive.

Ideally if one cylinder is not sufficient, the gas plan also shows other cylinders with the same mix and uses these. However this may not be as simple as it seems:

When should the gas plan switch to another cylinder with the same mix?
- When it is fully empty?
- When at 50 bar? But what if more gas is required and both cylinders are already at 50 bar, drain them at equal rates even further?
- Keep both cylinders (or more) at an equal level all the time? (side mount style?)
- Should this be user configurable?

Another question is: Should the dive plan show switches to other cylinders, but with the same mix? This is even harder to do, and with sidemount this is gonna be weird as you switch often to keep both cylinders balanced.

Current workaround:
Split the dive manually in smaller sections, and select specific cylinders for these sections, dividing the gas usage manually.

[mdeinum]

My current workaround, double the cylinder size.

I think a quick win would already be an option in the tank panel to select if they are double or not. I think that would cover the 80% case.

Another option would be to forget about tanks and just care about the mix and the volume of gas in liters being used.