When to refill CO2 tank?

[erwinx]

http://www.aquaticquotient.com/forum...Regulator-dial

Hi, I have the same Co2 regulator shown in the photo above. I bought the kit in October and running it at about 1.5bps.

Currently, the high pressure side is showing just under 300psi and the regulated pressure side has dropped to 25psi. Because I'm using an UP-Aqua inline diffuser which requires 30psi, the bubbles per second has slowed to something like 1 bubble every 1.5 seconds.

(1) Does 300psi on the high pressure side mean 1/3 full or...?
(2) Any way to increase the pressure on the regulated side since it dropped from 30psi to 25 psi? I used an allen wrench to twist the allen nut near the dials clockwise and anti-clockwise, didn't seem to have any effect.

Or is it time to refill?

Thanks!

[ltsai]

When the tank psi drops below 1000psi, it means is running out soon. Mostly gas and no more liquid insidr. Will need to top up soon.