The bubble rate you have set sounds high to me for a 20 gal. I run just
slightly less and 1 bubble per second on my 55 gallon tank. but you have
the bio wheel which will help you to lose a lot of the co2 you inject. I
would suggest you remove it.

Watch your pH level closely initially and use this calculator to calculate
your co2 level. Also watch for gasping fish - a sign of too much co2.

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

--
Bob Alston


http://members.cox.net/tulsaalstons/
"Bill Beam" wrote in message
...
I purchased a 5lb tank of CO2 and a regulator. I cut a small hole in
the bottom of my incoming filter pipe. I ran a hose from the
regulator to the bottom of the intake pipe. The pipe is clear and I
can tell I've got about 2-3 bubbles per second CO2. The intake pipe
goes through impeller - sprayed out onto mechanical filter and then
into biowheel. Does this sound like an adequate CO2 setup? Do you
think the bubbles will get diffused correctly in the impeller? On a
20g tank, could someone estimate the ph drop I might see at the rate
of CO2 I'm putting in? Thanks