I used this basic setup, minus the bio balls http://www.csd.net/~cgadd/aqua/co2.gif
$3.99 blue glass vase and
$3.50 for 6"x36"x2" sheet of foam at crafts store (plenty left over)
$9.99 for 1/4" glass cutting bit
$4.95 for ceramic/glass grinding dremel head
$0 Power head, and
$0 for air-stone I had laying around.
I don't have my CO2 bottle yet and waiting on my solenoid valve, but I think I designed it too well. I blew into the tube and the air absolutely will not escape my reactor. As you can see, an air bubble is created at the top and doesn't escape. Though I found out a bonus when the air gets low enough, the incomming watter churns up bubbles even more. The problem is this...if I had a CO2 canister with bubble counter setup, it would continuly fill with air until there was nothing but the sponge at the bottom.
Just for an experiment I put a hose in the air inlet mister built into my powerhead, letting large amounts of misted air in. Still with the entire reactor full of air, nothing would come out the bottom. It was weird! Some how when the air got to the foam, it let the water by with out pushing out the air.
-excelent exposure time of CO2 to water since the CO2 has no place to go but get spun up by the water.
-The air inlet on my power head would make an excellent place to hook up my CO2 suply to. The effect makes a much finer mist of bubbles then my air-stone
-With the CO2 being exposed for so long, I suspect my CO2 bottle will last a long time.
-CO2 build up has no place to go if it doesn't get absorbed into the water.
-can't think of anything else.
1) illiminate the air-stone, using the mister as the CO2 input and cut the tube connecting the airstone much shorter that so when the CO2 level gets to the end it will escape out the top.
2) Cut down the foam from 1" to 2" thick to possibly let some of the CO2 get through
3) Maybe the sponge isn't porus enough and needs to be so some of the air can escape with the water.
4) Get a more powerful pump so it forces the gas through the bottom.
5) If I tip the reactor sideways, a small strip of air forms at the top until it has enough presure to push by the foam and out.