# My CO2 cylinder is sweating outside



## mrbhala (Sep 13, 2018)

Hi,
After tried to find any existing thread for last 3 days, i am writing this. I am recently added CO2 to my low tech 30 gallon tank. I am using a aluminum cylinder (3 lts) with regulator, needle valve purchased separately and assembled myself. No leakage. But I can see a sweating on the cylinder valve and regulator. Is it normal or have to care about something? Usually it will happen with co2 welding. But I couldn't find any such thing mentioned related to aquarium co2 system on the net. Pls advice me.


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## PlantedRich (Jul 21, 2010)

You are having very humid weather where you live? That can also combine with the way gas cools when it changes pressure. As gas is let out of the tank, the remaining gas cools and that cooler tank can let condensation form. Like on a cold drink glass? I don't find it too often and it does come when gas is let off. Perhaps you are losing gas, which makes it more likely to happen, so a really good time to make sure there is not a leak which is missed. Be aware that the gauge will NOT begin to go down until all of the liquid has turned to gas, so the meter can't be used to find /watch for leaking. There may not be a leak but the penalty for missing a leak is that you will lose a whole tank of gas, so I go the extra to make sure. 
I do a leak tests with really thick soapy water like shaving cream and brush it all over any spot that might be leaking. I also have to put it on things that seem weird like the screws on the back of meters and the edge of the glass, as these can be spots where an internal meter leak will come out where we don't expect them. 
Perhaps there is not a leak and I am silly but it can save me time and money to avoid going after a new tank fill!! Perhaps your gas use and the humid weather is just too much? I see this more in propane tanks when used in cold weather.

Pleases, please, strap the tank to the stand , etc. to avoid accidents!


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## mrbhala (Sep 13, 2018)

PlantedRich said:


> You are having very humid weather where you live? That can also combine with the way gas cools when it changes pressure. As gas is let out of the tank, the remaining gas cools and that cooler tank can let condensation form. Like on a cold drink glass? I don't find it too often and it does come when gas is let off. Perhaps you are losing gas, which makes it more likely to happen, so a really good time to make sure there is not a leak which is missed. Be aware that the gauge will NOT begin to go down until all of the liquid has turned to gas, so the meter can't be used to find /watch for leaking. There may not be a leak but the penalty for missing a leak is that you will lose a whole tank of gas, so I go the extra to make sure.
> I do a leak tests with really thick soapy water like shaving cream and brush it all over any spot that might be leaking. I also have to put it on things that seem weird like the screws on the back of meters and the edge of the glass, as these can be spots where an internal meter leak will come out where we don't expect them.
> Perhaps there is not a leak and I am silly but it can save me time and money to avoid going after a new tank fill!! Perhaps your gas use and the humid weather is just too much? I see this more in propane tanks when used in cold weather.
> 
> Pleases, please, strap the tank to the stand , etc. to avoid accidents!




Thanks for your input. Definitely a leak was there. Guess a internal leak in the regulator. 3 L Cylinder gone empty within 3 days. Usually come for months with 2bps. Need to check seriously.


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## jeffkrol (Jun 5, 2013)

Most likely leak is the CGA stem to tank valve especially if using the paper/fiber discs.. Plastic/Teflon have always worked better for me and the CGA nut needs to be tightened.. good...


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## PlantedRich (Jul 21, 2010)

Sometimes leak checks are a bit more difficult than we first think as there can be two types of leaks and they will need different methods to find each. We think of the small leak as the hard to find one and it can be found with a good soap mix that is thick enough to cling to places and stay long enough for us to spot a really slow growing bubble. 
But then there are also times when we might miss a bigger leak as it can do strange things. We may spread the soap on and not see any bubbles, so we move on but get caught by a leak which simply blows the soap mix off! It may not blow any bubbles as the mix is gone! So we need to also move our hands slowly over things and feel for a cold draft! 
And it is certainly true that the most common leak is the one we create by using less than best tools. We should all get a good wrench that gives us good torgue to get that CGA 320 fitting good and tight. I prefer something like an an 8-10 inch "Crescent" -type wrench as they have smooth jaws that don't scar up the fittings. Doesn't have to be a Crescent brand but that style? Then it takes a bit of "feel" to get the right amount of pressure to make whatever seal work the way it is designed. Enough pressure to compress the seal nut but the seal lasts much longer if you don't try to kill it every time!


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## mrbhala (Sep 13, 2018)

Thanks all again. My tank PRV also gone on second fill. Now using the below method for testing. On LP gauge side there is a very meagre leak which could not be identified even with soap/foam. But pressure lists for only 3 hr in after regulator fittings. Seems ok. Everything in full tight with Teflon tape. Any suggestions pls.

https://www.plantedtank.net/forums/...ck-co2-pressurized-system.html#/topics/137245


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## jeffkrol (Jun 5, 2013)

Teflon tape is not "technically" a sealing media..
If you actually identified leak on the LP gauge just replace it.
"I" prefer using things like Rectorseal instead of tape.. 
https://www.plantengineering.com/si...sealant/5103ee62235def2053cec5d46dd34156.html


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## PlantedRich (Jul 21, 2010)

I do not use that particular test for my regs as it seems way too time consuming and really tells me things that I don't feel important. Small internal leaks which show gas is slowly moving between parts like diaphragms but staying inside the reg are not important to me. More technical faults which do not mean I am losing gas. 
I go for less demanding tests which show me where I might be losing gas to the outside. This can be as simple as putting a fitting on the output, where I might connect tubing, (a plug or cap?) open the tank valve and fill the reg with gas under pressure, and then closing the tank valve. This charges the reg body and meters with gas under pressure as both the input and output are closed. In this way, there is a small amount of gas trapped in all the smaller parts of the reg and should stay there, if there are no leaks to the outside. So I leave it for overnight or more and come back to look at the high pressure meter. The low pressure meter may go up as I don't expect the diaphragm inside to be a perfect seal but the high pressure should not go down as the gas is expected to be trapped! This drawing may help if one has not looked inside:
https://www.google.com/search?q=hig...KHWkfBV8Q9QEwA3oECAQQCg#imgrc=HZ2NtrMV7n3MQM:
But if the high pressure drops, I look for leaks and the meters are one that is hard to find but easy to explain why they might leak. The bourdon tube is made of foil, almost like a chewing gum wrapper and does break pretty easy is too much pressure it allowed to hit it. 
https://www.google.com/search?tbm=i...0j0i5i30j0i8i10i30j0i8i30j0i10i24.1alru33pa04
Asmall internal leak which may come out around the glass or the screws on back?


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## jeffkrol (Jun 5, 2013)

Some here have dumped the entire unit (tank/reg) underwater to find leaks.. Certainly not recommended though..


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## mrbhala (Sep 13, 2018)

Thank you. Leaking at the fitting joint after regs. As Jeffkrol said, Teflon is not a sealing agent. But managed to reduce the leak. So far running without issues. Will update soon. Once again thanks all.


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## jeffkrol (Jun 5, 2013)

Glad you figured it out.. Now the thing is the SEAL between the regulator and the tank valve is STRICTLY done by the 2 flat surfaces and the washer (or disc, or sometimes an o ring w/ a "perma-seal") between the 2.. Tape and dope is unnecessary here..

As I said, use the plastic washer and tighten REALLY secure..


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## PlantedRich (Jul 21, 2010)

But the same point always comes back when I think about where and why we might have leaks. They come in all kinds and types, whether it is simply a loose connection, using the wrong type seal for a particular fitting or a small beak in the tubing. 
I started out in air pressure using nitrogen where leaving a leak meant you got to go out there and drag a fifty pound tank through hell and high water again to replace it if you left a leak! Certainly made me a believer in checking my work, even when I KNEW it was good. The time/effort saved is just not worth the penalty of lost gas, time, and effort to do it all over again!


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## mrbhala (Sep 13, 2018)

Yes. As you already mentioned i used a nylon washer between cylinder and regs. Earlier the hard one which came with regs didn't do well.


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