>From: "Johnnie" <denjoh at ccse_net>
>Date: Wed, 4 Sep 1996 09:19:04 -0400
>I was wondering if anyone has tried this with home-brew "yeast CO2"
>injection.  Normally, there is just a tube from the bottle into the tank. 
>I want to know how it would work if there was a tube from a small air pump
>into the bottle, and another from the bottle into the tank.  That way there
>would be constant pressure in the bottle and constant bubbles in the water.
>Appreciate any thoughts...

I tried something very similar to this once.  It was a major disaster.
I came home one night after the set up was running for a couple of days and
found my tank water cloudy and half the fish dead.  From I could tell what
happened is that the air pump blowing air into the yeast bottle caused enough
foam so that the foam got ejected into the tank.  The yeast-sugar-water
somehow caused ammonia to built up in the tank.  I measured the ammonia levels
in the aquarium and that were off the scale for my test kit.  Luckly, I had
some Kordon AmQuel water conditioner and used it to quickly bring down
the ammonia levels. 

Perhaps pumping air into the yeast bottle might improve the CO2 generation,
but make sure that the yeast-sugar mixture doesn't get siphoned into your

Ron Wozniak  Allentown PA, USA