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Re: CO2 injection line-ups (was Aquatic plants blah we know already blah)

On Wed, 31 Jan 2001, Stephen Boulet wrote:
>> How about adding another possibility:
>> Bottle + Reg + Needle Valve + Glass diffuser
>> - - -----------------------------
>> PRO simple, not intrusive in tank, self-contained
>> CON none known   ;)

On 1 Feb 2001 Erik Olson replied:
> Having tried this myself, I can state:
> CON injection rate still not particularly adjustable, and still not super
> efficient.  And because of the double flow restriction (needle +
> diffusor), I found it's difficult to make adjustments to the needle valve
> once the diffuser is installed (the feedback takes on the order of an
> hour). It's better than NOT having the needle valve, but still not as good
> as using a true reactor system downline.

At first I was having the same difficulty. When you have a 
length of tubing after the regulator/needle valve and 
before the glass diffuser, this tubing operates as storage 
balloon. When you're making an adjustment to reduce the 
flow, it takes a long time for the stored gas to exit from this 
balloon through the diffuser and only after that you can see what 
the new flow rate is. What you need to do is let all the gas 
out of this balloon after each adjustment. I just have a 
connector piece after the regulator/needle valve that I 
can yank apart and vent the extra pressure from the tubing 
whenever I've made an adjustment to the regulator or needle 
valve. Doing this lets me do all the adjusting I need in just 
a couple of minutes.


Mr.  I L K K A   K A L L I O
San Jose, CA