CO2 reactor musings

Just a quick note to confirm what several have mentioned here as of 
late... the rate of water flow through your CO2 reactor can greatly affect
its efficiency.  

My current CO2 reactor consists of a 2" diameter clear acrylic tube that
has been bonded to a flat acrylic base on the bottom and epoxied to a
sequence of PVC reducing bushings so that it eventually ends up with one
of those 3/4" threaded plastic drip irrigation manifolds that has 4 small
taps hanging off it.  The water and CO2 are injected through two of the 
taps at the top (the other two are capped off), the CO2-laden water exits 
the bottom through a small hole drilled in the side.  The chamber is 
filled with Dupla mini-Kaskade (I got a real job last year, so I figured 
I'd splurge on at least one aspect). ( I detailed a previous generation of 
this reactor on the Krib as 
http://www.cco.caltech.edu/~aquaria/Krib/Plants/CO2/reactor.html )

Formerly, the water was injected via a flow-restricting drip irrigation
tap (the kind that limit it to 1GPH or 2GPH) into my tank return (from an
aquaclear-802 powerhead).  I had removed what I thought to be the flow
restrictor (a little rubber gizmo inside the tap), but it was still very
low flow, and tended to get clogged with random sump debris from time to
time.  Still, I have gotten moderate-to-good success with this unit.  I 
did not change the regiment, because I figured I was mostly losing CO2 as 
the water cascaded down to my sump from the main aquarium.  However, last 
weekend I replaced the tap with a less restrictive one (namely, those 
extremely cheap ones which are basically two opposing barbs with a 1/8" 
hole.  What a difference!  The pH has dropped from 7.0 to 6.5 with the 
same bubbling rate.

Anyway, thought I'd pass it on.  If I have time, I might do another 
illustration & update my reactor article.  I decided long ago that 
injecting the CO2 from the bottom was just no good, but the sketch 
doesn't represent this.

     - Erik

Erik D. Olson					         amazingly, at home
eriko at wrq_com