# How to release/lower pressure in DIY CO2 setup?



## caelumos (Mar 11, 2017)

Hey again.... :hihi:

I got my DIY CO2 soda bottle citric acid/baking soda system going, and it's been working pretty well for a few days. One thing I ended up doing due to some 'advice' was closing the valve at night to 'shut off' the flow. My pressure was pretty low on startup, so this was OK for a few days, but yesterday I noticed the pressure was at 2kg, so I let it run at night to hopefully keep it steady at that level. I wake up, now it 's gone up to 3.2kg. 

My question is, how do I lessen the pressure in the bottles before it climbs any higher? Is it possible? I'm terrified of opening those things without knowing what's going to happen lol, but I'd rather do it now than when the pressure is 6kg if someone lets me know it's OK.

Thanks in advance!


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## theatermusic87 (Jun 22, 2014)

Depending on what you have for a setup, I think there is a pressure relief built into the gauge (depending on who makes it I don't remember specifics). Other option is to open the bottles slowly (like you would a shaken bottle of soda) to vent some of the gas. I would open whichever bottle had the pickup tube in it, otherwise the pressure difference would just cause the system to dump a bunch of fresh acid in. Last but not least you can burp the system by opening the needle valve and dumping the co2 that way (you can turn it off briefly, disconnect the line to the aquarium, then reconnect when done)

You may need to restart the setup after doing this


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## caelumos (Mar 11, 2017)

theatermusic87 said:


> Depending on what you have for a setup, I think there is a pressure relief built into the gauge (depending on who makes it I don't remember specifics). Other option is to open the bottles slowly (like you would a shaken bottle of soda) to vent some of the gas. I would open whichever bottle had the pickup tube in it, otherwise the pressure difference would just cause the system to dump a bunch of fresh acid in. Last but not least you can burp the system by opening the needle valve and dumping the co2 that way (you can turn it off briefly, disconnect the line to the aquarium, then reconnect when done)
> 
> You may need to restart the setup after doing this


Thanks for the reply! I tried to 'vent' it by opening the needle valve but like you said, it did dump a bunch of acid in the other bottle, so I'm not sure I'll try that method again lol. I unscrewed the acid bottle a little and that worked perfectly. Thanks again for the reply! I couldn't find any info on what would work or be safe/not wasteful lol. I appreciate it.


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## JonA (Mar 8, 2017)

unscrew the bottle with the citric acid in it. That will bleed off pressure without charging acid into the baking soda solution. Don't unscrew it all the way though, just crack it slightly until pressure starts to drop.


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## jrill (Nov 20, 2013)

Leave it alone. It will take alot more pressure to burst the bottles. Raise the weight in the Acid bottle with a magnet to limit the amount of acid that is transferred when the pressure drops in the soda bottle.
Check out the end of this thread
http://www.plantedtank.net/forums/showthread.php?t=815241


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## Riyaz Ahmad (Mar 15, 2021)

DIY Co2 can get upto 85PSI, dont worry that wont blast off the bottle, now to reduce the pressure in your DIY Co2 simply unscrew your bottle with Citric Acide (Dont open it completely) until the pressure is back to green area. Thanks


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