# [Wet Thumb Forum]-CO2 System



## Revelation_04 (Feb 8, 2003)

Thanks in part to the help of you guys on here I've got my pressurized CO2 system set up. I got my Used 5lb Cylinder and a CO2 fill from Praxair,a welding supply shop($63),new dual guage Micromatic Pro-line regulator off E-bay($42),Clippard MNV-4K needle valve($11), and a reactor and tubing from Tom Barr($20), plus a few other misc expenses. I'd say I did pretty good, setting this up for about 140 bucks. The dang cylinder was the most expensive part. I set it up on my 29 gallon yesterday, and I'm still fine tuning. I was checking for leaks and found a few small ones around the threads that adapt my regulator to my tubing. I was wondering if the leaks really matter that much. I tried to put teflon tape on the threads, but they wouldn't tighten down very good even before I added the teflon tape. I just tried to get them as tight as I could then I just wrapped the tape like crazy. They don't leak as much now with the teflon tape, but they still leak a little. I can't wait to see my plants start to grow like crazy. I'll try to get some pictures soon. Thanks to everyone who helped me get my system set up.

-Myles


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## Revelation_04 (Feb 8, 2003)

Thanks in part to the help of you guys on here I've got my pressurized CO2 system set up. I got my Used 5lb Cylinder and a CO2 fill from Praxair,a welding supply shop($63),new dual guage Micromatic Pro-line regulator off E-bay($42),Clippard MNV-4K needle valve($11), and a reactor and tubing from Tom Barr($20), plus a few other misc expenses. I'd say I did pretty good, setting this up for about 140 bucks. The dang cylinder was the most expensive part. I set it up on my 29 gallon yesterday, and I'm still fine tuning. I was checking for leaks and found a few small ones around the threads that adapt my regulator to my tubing. I was wondering if the leaks really matter that much. I tried to put teflon tape on the threads, but they wouldn't tighten down very good even before I added the teflon tape. I just tried to get them as tight as I could then I just wrapped the tape like crazy. They don't leak as much now with the teflon tape, but they still leak a little. I can't wait to see my plants start to grow like crazy. I'll try to get some pictures soon. Thanks to everyone who helped me get my system set up.

-Myles


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## Rex Grigg (Jan 22, 2004)

Yeah the leaks matter, they matter a lot. You will lose 90% of your gas to those leaks. Even a small leak could empty a 5 lb cylinder in a week or less.

If the teflon tape is not working try another part. It should take no more than two wraps of the tape. If that doesn't work go try some plumbers dope. If that doesn't work then could be your regulator is worn out.

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## Revelation_04 (Feb 8, 2003)

So should I not even have very small leaks?


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## qbal18 (Jul 19, 2004)

!!NO LEAKS AT ALL!!!
when oyu have even just 1 small leak that is not regulated oyu dont know how small it rell is but lets sy it is so small that you can hardly even fell or hear it well if your tank shoudl last 9 months at 1 bpm a supper small leak will be alot more then that so even if your leak is say 1or 2 bpm you will loose at least 60% of your co2.


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## gsmollin (Feb 3, 2003)

> quote:
> 
> Originally posted by Revelation_04:
> ... I was checking for leaks and found a few small ones around the threads that adapt my regulator to my tubing. I was wondering if the leaks really matter that much. ...
> ...


Yes, of course they matter. You are losing a lot of CO2. Now I'm having trouble understanding which fitting is leaking. You should have the regulator at 1/4 inch FNPT, a 1/4-1/8 bushing, a 1/8 inch MNPT adapter for the needle valve, a 10-32 O-ring seal around the needle valve port, and a hose barb outlet on the needle valve. The most common place for a leak is the 1/4-1/8 inch bushing. If it leaks with 2 full wraps of Teflon tape on it, then it will not seal, and is defective. Replace it, and buy the replacement from someplace else.


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## Rex Grigg (Jan 22, 2004)

You want no leaks. None at all. No matter how small.

Hmm... I'm betting his system has a hose barb on the regulator. But one of those inexpensive brass fittings is leaking.

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## Doomer (Feb 2, 2003)

Would you like a small leak in your tire ?


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## Revelation_04 (Feb 8, 2003)

Thanks everyone. I look at my question and I realize that it was a pretty stupid one. I knew what you guys would say, but I guess I was just hopping someone would say very small leaks wouldn't matter or something. Like Rex said I do have a hose barb coming from my regulator since my needle valve is down by my bubble counter. From the regulator is a bushing then a hose barb. The leaks were coming between the regulator and bushing. I put teflon tape on the parts that were leaking, but they still leaked a little so I guess I'll try to get some different parts that fit together better. Thanks for all the help.


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## gsmollin (Feb 3, 2003)

I found a picture of this regulator on e-bay. You have to remove the hose barb, so you can connect the needle valve directly to the regulator. You don't want regulator pressure on a flexible hose. If you remove the leaking hose barb, you should see a 1/4 inch FNPT fitting. Get a 1/4-1/8 inch bushing to connect it to the Clippard 1/8 inch MNPT-to-10-32 adapter. 

Are you sure you don't have a Clippard MNV-4K2 valve? Thats the one with a 0.2 inch outlet hose barb. The MNV-4K has only a 10-32 female port, which is not too useful for aquariums, since that is where you want to attach the flexible hose.


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## Rex Grigg (Jan 22, 2004)

> quote:
> 
> You don't want regulator pressure on a flexible hose.


 Hmm... I wonder about this statement. What regulator pressure are you talking about? I'm running my low side at 15 psi and my flexible hose is handling it just fine. Even with a needle valve in the system I think you are going to have a pressure equilibrium in the system. If it's 15 psi on one side of the valve it's going to be close to that on the other side. But then again, I could be totally wrong here. It seems to me all the needle valve does it regulate the volume, not the pressure. If I'm totally off base here please educate me.

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## gsmollin (Feb 3, 2003)

A needle valve is an open-loop flow regulator. The gas flow through the needle valve is the same on the inlet and the outlet. The pressure on the inlet is higher than on the outlet. One should adjust the regulator so the inlet pressure is a minimum of 10 psi above the outlet pressure. This is to achieve flow-rate regulation, even when the pressure changes on the regulator, most often from an empty-tank-regulator-dump.

The outlet pressure of the needle valve is largely uncontrolled. It will be the sum of the back pressure of one's bubble counter, check valve, and CO2 reactor.

The reason for my recommendation to remove the hose barb is 1) its part of the leak problem and 2) it is potentially part of a future leak problem. I also think Revelation_04 should remove the ball valve, it can also leak. The CO2 system will work with regulator outlet pressure on the hose, but it's not as robust as a hard-plumbed setup. CO2 diffusion through the hose is also faster at higher pressure than at lower. This is an insidious form of CO2 loss, and is probably to blame for many short-run problems with CO2 setups.


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## Revelation_04 (Feb 8, 2003)

Man,I'm confused. Gsmollin, I did take off that big hose barb thing. What the heck is a ball valve? I connected a bushing to my regulator then attached a a hose barb to that. I think the needle valve is a MNV-4K. I'm at work right now, so I'll look when I get home. What the heck do I need to do? Should I leave it like it is or put the needle valve on the regulator? 

Thanks,
Myles


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## gsmollin (Feb 3, 2003)

Revelation, does the new bushing and hose barb leak? If not, then you may be done. Re-check all connections for leaks. You don't have to use hard plumbing between the regulator and needle valve, but it is more secure if you do. I only use flexible hose at the CO2 reactor. There are many ways to connect these things up, but I'm pretty picky about how I do it. You only need to do what works. 

If the Clippard needle valve has a hose barb on it, then it is a MNV-4K2. If it has a 10-32 female outlet port, its a MNV-4K.

The ball valve is the valve with the red handle on the outlet of the regulator. On second thought, don't touch it if its not leaking.


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## captain (May 12, 2006)

> quote:
> 
> One should adjust the regulator so the inlet pressure is a minimum of 10 psi above the outlet pressure.


How do you know when you have a 10psi differential? Is is just a guestimate?



> quote:
> 
> CO2 diffusion through the hose is also faster at higher pressure than at lower. This is an insidious form of CO2 loss, and is probably to blame for many short-run problems with CO2 setups.


Is there certain tubing that won't leak in this manner? Or is the solution to keep the run of tubing short and the pressure as low as possible while maintaining the 10psi diff?

-Steve


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## Revelation_04 (Feb 8, 2003)

I'm going to get the new parts tomorrow. I'll see how it works when I get home from basketball practice. I had somebody order the needle valve for me. I looked on the website and I think it is the MNV-4K. It came with 2 hose barbs with one attached via some other fitting. I don't know all those fitting terms yet, but I'm learnin. Thanks


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## Rex Grigg (Jan 22, 2004)

Then it is a MNV-4K2.

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## 2la (Feb 3, 2003)

Rex, I was actually told by the clerk at the outfit you recommended that the part I needed was the MNV-4K3 (IIRC), which has a 1/4" hose barb fitting for a snugger fit with standard silicone or CO2 resistant tubing (the MNV-4K2 has 1/8" hose barbs). He had to go back into the stockroom to get the appropriate parts for modification. Are you using a hose that's smaller than the usual aquarium air line tubing?


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## Rex Grigg (Jan 22, 2004)

Nope. I use the K2 barbs and they work fine. I use the standard green silicone tubing.

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## gsmollin (Feb 3, 2003)

There's a lot of cross-traffic on this post.

Captain: If one shuts off the cylinder valve, the outlet pressure of the regulator will drift down to the back pressure of the Reactor, check valve, bubble counter. Its mostly check valve, and this number will be highly variable. Mine is 1 psi reactor (by analysis) and 11 psi check valve. So, you would need to set the regulated pressure at 22 psi to get about 10 psi across the needle valve. If you wanted to know for sure, you would need to tee-in a gauge, temporarily.

There are several types of "CO2 resistant" tubings available. One sells with the trade name "Tygon". Others sell without trade names, probably to protect the profits of aquarium dealers. Most are forms of polyethylene, high density polyethylene, or cross-linked polyethylene. I bought some of it from M3 about 3 years ago, for $.99/ft. It is pretty stiff, and I suspect its imported, because its 4 mm diameter. Silicone tubing is more permeable, and will lose more CO2 than the HDPE, but many people don't care.

2la: The "1/8 inch" hose barb on the MNV-4K2 is actually about 0.200" in diameter, across the barb. I think its designed to work with 1/8" to 4 mm tubing. A 1/4 inch barb sounds too large for most aquarium tubing.


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## 2la (Feb 3, 2003)

I'm using Hagen tubing of standard "aquarium" size. The barbs are either 3/8" or 1/4" in diameter and the tubing fits over it perfectlly. Perhaps the 1/8" barb works (well, obviously it does), but I like the tighter fit afforded by the larger hose barbs.


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## BobAlston (Jan 23, 2004)

> quote:
> 
> Clippard MNV-4K needle valve($11


where did you get the Clippard valve? If direct from them, they charge $5 shipping and $10 handling - in addition to the cost of the valve. Robert H. charges $18 or 19 (I assume it is the same one). I got mine at a "Robert Competitor" but recall the price was about the same. Shame mine didn't come with the 1/8-inch NPT female - 1/4-inch male NPT adaptor so I could easily connect it directly to the regulator.

Bob

[This message was edited by BobAlston on Wed March 19 2003 at 11:20 AM.]


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## Revelation_04 (Feb 8, 2003)

I had a friend pick one up from a disributor and sent it to me. I bought it for $11.


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## Robert Hudson (Feb 5, 2004)

> quote:
> 
> There are several types of "CO2 resistant" tubings available. One sells with the trade name "Tygon". Others sell without trade names, probably to protect the profits of aquarium dealers. Most are forms of polyethylene, high density polyethylene, or cross-linked polyethylene. I bought some of it from M3 about 3 years ago, for $.99/ft. It is pretty stiff, and I suspect its imported, because its 4 mm diameter. Silicone tubing is more permeable, and will lose more CO2 than the HDPE, but many people don't care.


The tubing I sell is polyethylene, and is actually made by Clippard. It is 1/8 tubing. Silicone tubing, including the Hagen "green" tubing is silicone, and will degrade, crack, and leak. You don't want 1/4 tubing unless you have 1/4 barbs.

Polyethylene tubing is more rigid and not very pliable. If you have trouble fitting it on a barb, you just have to heat the end of the tubing...then it will slide on.

Robert
King admin
www.aquabotanic.com


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## BobAlston (Jan 23, 2004)

Rex -

Please clarify re the Clippard MNV-4k2. As I understand it, it comes with a single 1/8 hose barb, with male 10-32 screw, that connects to the side port. Right?

Earlier, Revelation_04 said his came with two 1/8 barbs. Do you know how this connects to the other port, which I believe is a 10-32 male port?

Bob

[This message was edited by BobAlston on Thu March 20 2003 at 09:04 AM.]


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## Rex Grigg (Jan 22, 2004)

Chekc this out... http://www.clippard.com/store/display_details.asp?sku=MNV-4K2

The MNV-4K2 comes with two barbs. What happens is you get it really comes with an adaptor that the second barb screws into.

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## BobAlston (Jan 23, 2004)

Rex - I believe the MNV-4k2 comes with only one 1/8-inch hose barb. YOu have to buy an adaptor if you want to add a 2nd hose barb to the 10-32 male port on the bottom.

Bob


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## gsmollin (Feb 3, 2003)

I have the Clippard catalog 189, "Minimatic Valves". On page 19, the MNV-4 Fine adjustment needle valve is listed. Here is is the table for the MNV-4K style, which has the adjustment knob:
Part No. Female Port
MNV-4K 10-32 thd.
MNV-4K1 1/16" barb
MNV-4K2 1/8" barb
MNV-4K5 M5 metric thd.

The outline drawing shows a 10-32 male inlet port for all cases. The 10-32 gas connection was invented by Clippard, for their miniature flow control systems. They really push it. It's actually a drawback for what we do, since in no case is another 10-32 port available in a CO2 system, so some sort of adapter is required. I haven't been able to find a hose-barb-to-10-32-female adapter anywhere in the Clippard catalogs I have.

Later: I found a Female Hex Connector P.N. 15004, that would convert the 10-32 male inlet port to a 10-32 female. Then one could attach a 10-32 to 1/8 inch hose fitting P.N. 11752-1.


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## BobAlston (Jan 23, 2004)

>I haven't been able to find a 
>hose-barb-to-10-32-female adapter anywhere 
>in the Clippard catalogs I have.

11752-1-PKG

http://www.clippard.com/store/display_details.asp?sku=11752-1-PKG#

or

11752-4-M5-NP-PKG 
(I think this is what comes with the MNV-4K2)

http://www.clippard.com/store/display_details.asp?sku=11752-4-M5-NP-PKG

Note since the MNV-4K2 comes with ONLY one 1/8 hose barb, if you want a second, you will need to order an adaptor for 10-32 Male to 1/8 hose barb - such as:

S4F-PKG

http://www.clippard.com/store/display_details.asp?sku=S4F-PKG

Bob

[This message was edited by BobAlston on Thu March 20 2003 at 05:30 PM.]


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## Jim Miller (Feb 3, 2003)

The paintball folks also have 10-32 fittings. Take your setup bits to a paintball shop and you'll likely get the fittings you need.

jtm

Tank specs in profile


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## gsmollin (Feb 3, 2003)

The female-hose barb adapter SF4 is a swivel. Its less reliable than a hard connection. The swivel joints are susceptible to very small leaks. Swivels are good when you need them on a tight fitting chassis, but remember most of this equipment is optimized for flow rates 100X what we are using in an aquarium. I recommend all hard connections without swivels or unions.


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## BobAlston (Jan 23, 2004)

gsmollin -

Know of a non-swivel alternative to the SF4? I didn't find one in the catalog. But guess you could use the female-female connector and then the same hose barb. I was just looking for a single piece vs. multiple pieces.


Bob


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## Rex Grigg (Jan 22, 2004)

Ok, I guess I'm blessed with a awesome counter guy where I get my Clippard stuff. What I get is the MNV-4K2, a 15004, and a 11752-3. That gives me two barbs.

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## BobAlston (Jan 23, 2004)

Rex -

Great to have such good luck as you do. *grin*

Bob


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## BobAlston (Jan 23, 2004)

Rex -

Further thought. I believe Clippard provides its dealers with an "adaptors kit". I think I saw one on E-bay. Anyway, assuming this is the case, their standard business practice may be to provide whatever adaptors are necessary to make the valve work for you.

Besides the two adaptors are $3 and $4 for packages of 10 each.

Bob


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