"Dave" wrote in message ...
I use Fleischmann's "Active Dry" yeast, so this information may not be
relevant to you, but here goes anyway ....

I use two 64 oz. juice bottles to supply DIY CO2 to my 29 gal heavily
planted tank. I have the tubing "T"ed together and going to a Hagen Natural
Plant system diffuser. Each bottle has a mixture of 2 cups sugar, 1/2 tsp
baking soda, and 1/4 tsp yeast, which I've found I need to let sit for about
a day after mixing before I get optimum output.

I swap out the bottle containing the oldest mixture every three weeks ... I
just thrown the mixture away and replace the bottle with another one
containing a new mixture that's been sitting for a day. I get fairly
consistent CO2 production this way. The one issue is that the room
containing the tank can get fairly warm during the summer if my wife chooses
to not use the a/c that day ;-), and this increases CO2 production quite a
bit. I used to use an air pump on a timer to control pH drop at night, but
was never able to get it adjusted quite right, and this also didn't address
the warm-room-during-the-day issue. So now I use a CO2 controller, set to
turn on the air pump when the pH drops too low.

"Dances With Ferrets" wrote in message
om...
For any who may be familiar with the 2-liter-soda-bottle method of CO2
production... using baking soda as a buffering/stabilizing
compound... Could someone tell me what the optimum mix of water,
yeast, and baking soda would be using this method? (in case it makes
a difference in the formula, the yeast culture in this case is an
ethanol-resistant strain commonly used in wine-making). Also, how
often would one recommend refreshing the solution in the bottled
culture? Or would it be best to discard the culture and start a new
one? If discarding, how far in advance should the new culture be
started to supply a consistent amount of CO2?

Dave, and others,

I have just today hooked up a DIY/CO2 in my 12 gal Eclipse, and am
keeping my fingers crossed. What puzzles me is the startup. I was
doing a bit of improvising on the container, and so I wanted to do a
test run just in my kitchen, bubbling into a glass. Curiously, I found
that it was NOT working. I opened it up, shook it around a bit, closed
it up, and presto bingo, I started to get bubbles. Prior to that, it
had been sitting there for close to a day with virtually no action. So
my question is, when you first mix up your batch, and you let it "sit
for about a day", is that open or closed up (aerobic or anaerobic)?
Mine was closed and didn't really get going until I stoked it with
some air.

As an aside on this whole CO2 injection thing, does anyone know of
using the CO2 cylinders for paintball guns and bike tire inflators as
a small source of CO2? I know that they only come in 8g, 16g, and 25g
sizes, but for a small tank like mine I think that 25g would last a
few weeks. That is based on the assumption that I lose 15mg/l/day,
which is an out-of-the-air guess. The benefit (to me, at least) is
that a small tank setup can't elegantly accomodate a large CO2
cylinder and regulator -- seems like overkill.

Any opinions or personal experience?

-- tomo