# Single stage CO2 Regulator, becomes unstable when gas is about 20% left in the tank, is that normal?



## enb141 (23 Oct 2020)

Hi, this is another thread from another CO2 regulator that I have, is a Tunze single stage, the problem that I have is that when the gas on the co2 tank begins to deplete (when the tank has about 20% left) it starts to become unstable, with unstable I mean it starts to release way more gas, for example if I set it to 3 bbs, when it reaches the end of tank, the regulator releases 20 or 30 bbs.

Is this normal or is this CO2 regulator failing to?

I'm asking this because I know that single stage CO2 regulators releases the gas when they are about to get depleted, so I don't know if the behavious or my tunze is normal or is it broken.


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## Matt1994 (23 Oct 2020)

Enb141 hi!
Sorry to jump onto your post 
I am not to sure on the answer myself but am in the middle of setting up an aquascaper 600 and part of my kit is the strideways Pro reg which I also belive is single stage so would be good to hear the answer also ! 
Sorry to hijack your post 


Regards 
Matt


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## RudeDogg1 (23 Oct 2020)

I have heard this before but never had it happen with my old jbl set up


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## Mr.Shenanagins (24 Oct 2020)

That is the general warning given when using a single stage regulator. It’s not everyone’s experience, but it does happen. I have a Victor HPT270C that I acquired on eBay a couple years back for $50. It’s a medical grade, high purity two stage regulator. I can literally run the CO2 until the tank is empty with consistent low pressure side readings. The high pressure slowly depletes in the weeks leading up to it emptying.
Moral of the story, if you want reliability and just better overall quality, get a two stage.


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## enb141 (24 Oct 2020)

Mr.Shenanagins said:


> That is the general warning given when using a single stage regulator. It’s not everyone’s experience, but it does happen. I have a Victor HPT270C that I acquired on eBay a couple years back for $50. It’s a medical grade, high purity two stage regulator. I can literally run the CO2 until the tank is empty with consistent low pressure side readings. The high pressure slowly depletes in the weeks leading up to it emptying.
> Moral of the story, if you want reliability and just better overall quality, get a two stage.


Yeah, that's why I got a second hand GLA dual stage, but unfortunately it has leaks 

By the way a guy at r2r recommends a cheap single stage CO2 regulator and he claims that what happens to me, doesn't happens to him, that's why I created this thread here to see if others like me have issues or if I'm the only one with issues, that means that this CO2 is also broken.


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## Tim Harrison (24 Oct 2020)

I often use an UpAqua single stage reg. I've never really had end of cylinder dump. It gets a bit erratic once the cylinder is very nearly empty. But I usually change the cylinder out before that happens anyway.

It shouldn't really happen with 20% of the cylinder left. I think paying a little bit more for a good quality reg is an absolute must. I'd recommend a CO2 Art reg. Cheap regs can be a shortcut to self-sabotage...


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