How long can a 1L co2 tank last for?

[Mookie]

Let's say 2bps?

[Urban Aquaria]

How long that tank size will last would also depend on the daily duration of your Co2 injection, as well as the relative bubble size (different bubble counters may have slight different bubbles sizes) and the initial filled up volume/main pressure of the Co2.

But just for reference (so you could roughly work out an estimate), my 2L Co2 tank running at an average of 1 bps / 8 hours a day, lasted for around 10+ months until i saw the main pressure gauge start decreasing from its initial 1,100 PSI (which means the Co2 is no more liquid form, only gas form left, therefore running out soon). It probably could last another few more weeks but i "kiasu" and refilled it earlier to avoid a surprise later on.