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Old 20-04-2003, 07:10 AM
Michi Henning
 
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Default DIY CO2 diffuser

"Cannibul" wrote in message
...
On Fri, 25 Oct 2002 17:19:54 GMT,
(redled) wrote:

In my 10g tank, i use one 2L pop bottle. For the diffuser I use an upturned
cup that is about 2" in diameter, and it works just fine. I'd guess that
using this setup, at least half of the CO2 bubbles out of the tank, and the
rest dissolves. But, it stays at about 15ppm which is good for my needs.

In
my 55g tank, I have been trying to use the same method but with 2 2L pop
bottles and part of a plastic 500mL milk container as the upturned cup. It
has about 4 times the surface are of the other one, and again probably half
of the CO2 bubbles out. But, I can only reach about 10ppm, which is too low
(I'm aiming for about 20). I want to stay with a simple setup, without

using
a powerhead. I really can't afford one for now but I'm hoping someone else
out there has built a better diffuser than me and will share thier secrets.
I've tried using a piece of rigid tubing filled with marbles, gravel, and
various other things to try and make tiny bubble that might dissolve better
but I've had no luck. Any ideas?


I recently installed an Aqualine CO2 reactor. You can find a picture at
http://www.ab-aqualine.de/eng/index_e.htm. (Look for the CO2 section,
Reactor 1000.) This works like a charm -- 100% of the CO2 dissolves.

A number of people have built such a thing themselves. Basically, you
need a tube with a lid and a barb both ends. Fill the tube with bio balls
and plumb it into the filter outflow. (Water goes in at the top and flows
out at the bottom.) The CO2 connection is at the top in this model, but
the actual outlet for the CO2 is at the bottom of the reactor. (There is
a small tube that runs down the length of the reactor on the inside
from the CO2 connection at the top. The CO2 bubbles get trapped in
between the bio balls and are trying to rise against the downward
current of the water. This basically gives you indefinite contact
time, allowing all of the CO2 to dissolve.

The only other part of the reactor is a bleeder valve: simply a
bit of pipe at the top with a tap. This allows you to bleed off
air so the entire contraption can fill with water.

If you are handy with bits of PVC, it shouldn't be hard to build
something very similar at very low cost.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
Triodia Technologies http://www.triodia.com/staff/michi