how to fill oxygen tank

[Nanook]

I have a empty tank, How do I refill this tank?

[Tex]

Go to the surface. It will refill. They auto refill when you get to breathable air.

[Nanook]

Do I unequip it?

[QueenPixxa]

No, just leave it where it is. It will refill as soon as you resurface.

[Nanook]

Okay I will try this on one of my empty tanks. Oh boy that was too easy if it works

[Amanoob105]

As soon as you are in an area with air (surface of the water, on land and/or inside a powered building) your tank will refill if it's equipped.
As soon as you start upgrading your tank you won't need more than one most of the time. Less so when you start making vehicles.

[Coops]

The tank that you have equipped will refill. If you have other tanks, they need to be swapped out and equipped as well. Otherwise they stay in your inventory as empty.
At least I think that's how it works, I only ever use one tank.

[Nanook]

The empty tank did not refill when equipped. ???

[boki.san]

It will only refill the 'equipped' tank, not ones that are in your inventory

[boki.san]

so surface or go inside, then swap the empty tank to "equipped", and it will fill

[boki.san]

If your equipped tank is not refilling when you are in an aired space, something is broken ... I've never heard of that type of issue with tanks

[dragonbornzyra]

Would you rather have 3 mins or 6 mins of air?

But seriously, the equipped oxygen tank should be refilling. I mean, if it's not, that's a new bug for me.

[Nanook]

I figured it out that when I surface the tank is refilling. Many thanks for your help

[Bob Lord]

remember that 45 seconds of air is in your lungs. So when you switch tanks, don’t expect to see a full gauge if you’re down to to less than 45 with the old tank