Re: CO2 Reactor Idea

About two weeks ago, I posted the idea of using my wet/dry filter as a CO2 

>I'm searching for an idea for a CO2 reactor that will fit within the 
>limitations of my system.  Since my 110 planted tank serves as a room 
>divider, I don't want anything hanging off it and prefer not to have any 
>mechanical equipment in it.  So far, the only mechanical item in it is the 
>return from the W/D filter.
>Currently, I use an inverted "Tuperware" container for CO2 absorption.  It 
>fits in the plenum area of the wet/dry filter.  However. it does not have 
>sufficient surface area to achieve my desired CO2 levels (The highest I 
>have measured is about 8 ppm using a LaMotte test kit.

I have since this posting started using the w/d as the CO2 reactor.

Some of the results:

a.  Start:  using a 6" x 10" inverted Tuperware container for the CO2     
absorbtion with a CO2 rate of ~60 bubbles/min resulted in 6 ppm CO2.

b.  Since I was tinkering with CO2, I added a return sparger to the w/d 
return to achieve subsurface water return instead of a return to the water 
surface.  Consistent with  George Booth's article in the KRIB, the reduced 
surface turbulence increased the CO2 from 6ppm to 8 ppm, at the same 60 
bubbles/min rate.

c.  Next, I started adding the CO2 at the 60 bubble/min rate to the chamber 
of the w/d filter below the water's surface.  After 2, 4 & 8 hours, I 
tested the water.  Results were the same for each test:  8 ppm CO2, and no 
detectable amounts of NH3 or NO2-.

d.  After, 24 hours I increased the CO2 rate to about 100 bubbles / min.  
Testing after 4 hours showed the CO2 increased to 12 ppm and again there 
were no detectable amounts of either ammonia or nitrites.  Tests at 24 & 48 
hours also showed the same results.

IMO, these data indicate:  

1.  The w\d filter is a very good CO2 reactor (I did seal it up before 
starting to add the CO2.)

2.  Harmful levels of ammonia and nitrites did not form indicating that     
    a.  The bio activity in w/d filter is still functioning well or 
    b.  The plants and the bacteria on them and other components of my      
        setup  are adequate for bio filtration and have taken up any        
        diminished w/d bio activity. 

Tank info:

110gal, gH~4 degrees; kH~40 ppm; pH 6.7-6.8, Nitrates-25 ppm and dropping, 
phosphates-0.2 ppm and I hope dropping; & 2-110 watt VHO bulbs