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Old 17-07-2003, 09:43 PM
Matt Hanson
 
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Default why is my bubble rate changing?

I've had a very bad problem over the last few days with my brand new
high pressure CO2 setup. (not DIY!)

I cannot keep a constant bubble going for more than a few days at a
time. Here are the factors that I have eliminated:

1) not too long of a length of tubing, to or from anything. Shorter
tubing would eliminate any kind of pressure hold. Additionally, I ran a
very short length of the larger diameter line, for this very reason.

2) constant temperatrue - not sure if even a change of 20 degrees would
have much effect, but nonetheless, it's not a problem.

3) no leaks - I bubble tested with soapy water.

4) not a regulator or valve disturbance - very sure.


So then, I have checked these things, and found nothing to be out of the
ordinary. Yet, one day I have 1.5 bubbles per second, the next day,
about 1 bubble every 10 seconds.

Does anybody else have this kind of experience?

BTW - for what it's worth, I have one of those "needle valves" from Home
Depot. I'm already starting to suspect the problem might be somewhere
there. It's not even really a needle valve, so the control is less than
desireable. I'm not quite sure how they can even be marketed as a
needle valve. Tell me folks, is it in the valve?


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Old 17-07-2003, 09:43 PM
Scott Rogahn
 
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Default why is my bubble rate changing?

My bubble rate takes some time to become stable. The key is to make small
adjustments and check after a long settling time.
Like you I am using a cheap needle valve from a local hardware store.
When this valve is completely closed I can get about 45 bubbles per minute
if I adjust the pressure to ~4 pounds. If I crack the valve just a fraction
of turn the bubble rate goes way up. So for me it is best to leave it
'closed' and adjust my rate by pressure. I will make 1/2 to 1/4 turn at the
presure regulator and check after a hour or so. After a few tweeks over a
couple of days every thing remains stable. Leaving the needle valve alone
and adusting presure may go againt convetion wisdom, but it works for me.

Scott


"Matt Hanson" wrote in message
...
I've had a very bad problem over the last few days with my brand new
high pressure CO2 setup. (not DIY!)

I cannot keep a constant bubble going for more than a few days at a
time. Here are the factors that I have eliminated:

1) not too long of a length of tubing, to or from anything. Shorter
tubing would eliminate any kind of pressure hold. Additionally, I ran a
very short length of the larger diameter line, for this very reason.

2) constant temperatrue - not sure if even a change of 20 degrees would
have much effect, but nonetheless, it's not a problem.

3) no leaks - I bubble tested with soapy water.

4) not a regulator or valve disturbance - very sure.


So then, I have checked these things, and found nothing to be out of the
ordinary. Yet, one day I have 1.5 bubbles per second, the next day,
about 1 bubble every 10 seconds.

Does anybody else have this kind of experience?

BTW - for what it's worth, I have one of those "needle valves" from Home
Depot. I'm already starting to suspect the problem might be somewhere
there. It's not even really a needle valve, so the control is less than
desireable. I'm not quite sure how they can even be marketed as a
needle valve. Tell me folks, is it in the valve?



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Old 17-07-2003, 09:43 PM
Bob Alston
 
Posts: n/a
Default why is my bubble rate changing?

If you ever want to consider something a notch better, the Clippard needle
valve, MNV-4k2, is widely used for high pressure aquarium CO2 and can be
obtained from a Clippard distributor, if there is one in your city - check
www.clippard.com - for $10.10 If no local Clippard distributor, you can get
it from M3, Aquabotanic, florida Driftwood and likely others for 20-25$ plus
shipping. Better than your "cheapo" but not great.

To learn more about needle valves, maybe more than you ever wanted to know,
take a look at my web site:

http://members.cox.net/tulsaalstons/...Pressure%20CO2

Look at item #3 - CO2 needle/metering valves

--
Bob Alston

http://members.cox.net/tulsaalstons/
"Scott Rogahn" wrote in message
...
My bubble rate takes some time to become stable. The key is to make small
adjustments and check after a long settling time.
Like you I am using a cheap needle valve from a local hardware store.
When this valve is completely closed I can get about 45 bubbles per minute
if I adjust the pressure to ~4 pounds. If I crack the valve just a

fraction
of turn the bubble rate goes way up. So for me it is best to leave it
'closed' and adjust my rate by pressure. I will make 1/2 to 1/4 turn at

the
presure regulator and check after a hour or so. After a few tweeks over a
couple of days every thing remains stable. Leaving the needle valve alone
and adusting presure may go againt convetion wisdom, but it works for me.

Scott


"Matt Hanson" wrote in message
...
I've had a very bad problem over the last few days with my brand new
high pressure CO2 setup. (not DIY!)

I cannot keep a constant bubble going for more than a few days at a
time. Here are the factors that I have eliminated:

1) not too long of a length of tubing, to or from anything. Shorter
tubing would eliminate any kind of pressure hold. Additionally, I ran a
very short length of the larger diameter line, for this very reason.

2) constant temperatrue - not sure if even a change of 20 degrees would
have much effect, but nonetheless, it's not a problem.

3) no leaks - I bubble tested with soapy water.

4) not a regulator or valve disturbance - very sure.


So then, I have checked these things, and found nothing to be out of the
ordinary. Yet, one day I have 1.5 bubbles per second, the next day,
about 1 bubble every 10 seconds.

Does anybody else have this kind of experience?

BTW - for what it's worth, I have one of those "needle valves" from Home
Depot. I'm already starting to suspect the problem might be somewhere
there. It's not even really a needle valve, so the control is less than
desireable. I'm not quite sure how they can even be marketed as a
needle valve. Tell me folks, is it in the valve?





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Old 17-07-2003, 09:43 PM
Dave Millman
 
Posts: n/a
Default why is my bubble rate changing?

Scott Rogahn wrote:

My bubble rate takes some time to become stable. The key is to make small
adjustments and check after a long settling time.
Like you I am using a cheap needle valve from a local hardware store.
When this valve is completely closed I can get about 45 bubbles per minute
if I adjust the pressure to ~4 pounds. If I crack the valve just a fraction
of turn the bubble rate goes way up. So for me it is best to leave it
'closed' and adjust my rate by pressure. I will make 1/2 to 1/4 turn at the
presure regulator and check after a hour or so. After a few tweeks over a
couple of days every thing remains stable. Leaving the needle valve alone
and adusting presure may go againt convetion wisdom, but it works for me.


Scott,

It doesn't sound like your needle valve is much of a valve!

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Old 17-07-2003, 09:43 PM
Dave Millman
 
Posts: n/a
Default why is my bubble rate changing?

Matt Hanson wrote:

I've had a very bad problem over the last few days with my brand new
high pressure CO2 setup. (not DIY!)

I cannot keep a constant bubble going for more than a few days at a
time. Here are the factors that I have eliminated:

(snip)
BTW - for what it's worth, I have one of those "needle valves" from Home
Depot. I'm already starting to suspect the problem might be somewhere
there. It's not even really a needle valve, so the control is less than
desireable. I'm not quite sure how they can even be marketed as a
needle valve. Tell me folks, is it in the valve?


Your suspicion is correct!



  #6   Report Post  
Old 17-07-2003, 09:44 PM
Aqua
 
Posts: n/a
Default why is my bubble rate changing?

" BTW - for what it's worth, I have one of those "needle valves" from Home
Depot. I'm already starting to suspect the problem might be somewhere
there. It's not even really a needle valve, so the control is less than
desireable. I'm not quite sure how they can even be marketed as a
needle valve. Tell me folks, is it in the valve?


If you are using any check valve, that could be the problem too.

I am using the same "cheapo" home depot needle valve for the past one year
and my 5 lb. tank is coming around 6 to 7 months. My output pressure is 15 -
20 psi. Currently I have 80 bubbles per minute. I would suggest you to
tighten the top "nut" (the one below the 'T') if you really suspect the HD
needle valve.

Post your findings.

--
Thank You

Dominic
http://www.dlink.org/aqua





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