# [Wet Thumb Forum]-Low Pressure CO2 system components.



## sjogren1 (Feb 23, 2004)

What are the required elements of a LOW pressure CO2 system? Can a LOW pressure system be equipped with a pH controller?


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## sjogren1 (Feb 23, 2004)

What are the required elements of a LOW pressure CO2 system? Can a LOW pressure system be equipped with a pH controller?


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## Wheeler (Feb 8, 2004)

The required elements are just what you would expect:

Tank-> Regulator-> Needle valve-> Check valve (optional, I guess)-> Reactor.

Of course you can use a controller. It would look like this:

Tank-> Regulator-> solenoid w/ controller (totally optional)-> needle valve-> check valve-> etc.... 

The old high pressure setup was like this....It's been pretty decisively deemed unsafe:

Tank-> regulator-> check valve-> diffuser

Best wishes,
John Wheeler


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## sjogren1 (Feb 23, 2004)

John, would a metering valve be any better than a needle valve? And what the heck is a metering valve? I'm engineering challenged.


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## Wheeler (Feb 8, 2004)

I don't know what a metering valve is....Seems to me that it's sold as a step up from needle valves, though, but I don't know for sure.

Best wishes,
John Wheeler


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## sjogren1 (Feb 23, 2004)

John, I'm going to open some related topics regarding the individual components. I'm deciding on going this route as the inconsistancies of DIY Yeast Bottle type and Carbo-Plus frustrate me. I know the initial outlay is greater and it will delay my purchase of other toys, but I want to go over 3w./gal.and hate algae.


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## Wheeler (Feb 8, 2004)

It really is the best way to go. I don't know how I got along without my gas set-up.

Best wishes,
John Wheeler


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## imported_Fred (Feb 1, 2003)

Roger,
I believe a metering valve is just a glorified needle valve, maybe a little more precise. I think there was a lengthy discussion on the Krib about them.

Fred


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## sjogren1 (Feb 23, 2004)

Thanks Fred, I'll have a peek.


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## Rex Grigg (Jan 22, 2004)

A metering valve is basically just a much more precise needle valve. And a lot more expensive. Only real techo-geeks, anal-retentive engineers or those with more dollars than sense will feel the need to have a metering valve over a needle valve.

Semper Fi


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## david lim (Mar 30, 2004)

hello all,
i've found some nice metering valves for cheap around $24. These include the nupro s and m series and the swagelok ss-4mg. The nupro m and swagelok 4mg have cV ratings of 0.03, and the nupro s has a cV=0.007 (?) but I might be wrong. All are brand new... so far. if you don't mind ebay you can find some great deals.









david


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## sjogren1 (Feb 23, 2004)

Thanks guys. And Rex, even at this late (East Coast) time, I thoroughly enjoy your colorful replies.


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