It sounds like I must be doing pretty good with my DIY Co2 setup. I
am using a 2 liter bottle and the nutrafin diffuser. My tank is a 60
gallon. I use the following mixtu 4 cups of warm water, 2 cups of
sugar, 1 tspn yeast. Gently shake together and in approx 20 minutes
it is ready for the tank. I get 1 bubble oer second with this setup
which will last for about the first 3 days. From there, the bubble
count will slowly reduce to 1 bubble every 3-4 seconds or so. I
change the bottle every week. I did find that the "red star" brand of
yeast seems to work better than the others (not sure why).

This setup has provided my 60 gallon tank with more than enough Co2.
My plant growth has been excellent and the ph stays steady at 7.6. I
get pearling throughout the entire tank.

One thing I experimented with and think works well, is that I made
sort of a non-flow area in the tank. In other words, one half of the
tank has a lot of water flow as provided by the aquaclear 500 power
filter. the other half of the tank has almost no current since I
planted lots of tall plants such as cabomba, hygro, foxtail, ambula,
and anubias. This is also the side where the Nutrafin diffuser is
located. I think that the calm water allows for much more diffusion
of the Co2 into the water. The plants on the side with the current
show signs of Co2 fertilization since they are pearling as well and
are growing steadily.

I have also found that the Co2 bubbles will get "stuck" to the wall of
the Nutrafin diffuser quite frequently. Any more suggestions for this
one?

I hope this helps anyone willing to try.

Dave


(David Wee) wrote in message ...
In article om,
Robert Flory wrote:
"David Wee" wrote in message
...

Another thought:

It seems that one can achieve a maximum CO2-water diffusion *rate* with a
powerhead/filter intake + bubble system, but retention of the CO2 will be
based on the water chemistry (pH, kH, not clear on this, but indeed it
seems chemically related).

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

Assuming no other buffering ions... there is a direct relationship between
pH, KH and CO2. Chuck Gadd has a calulator ... "The formula used for this
calculation is: CO2 (in PPM) = 3 * KH * 10( 7-pH ) where KH is Carbonate
Hardness in degrees. " The (7-pH) is an exponent, the formating got lost
in the cut and past.

Ahh. So is "CO2 = 3KH * 10^(7-pH)" an equation or a function? I.e. CO2 =
f(KH, pH). The differentiation matters if KH and pH are independent of
each other, so I am asking if kH and pH are independent.



I don't think water chemistry has anything to do with CO2 retention. That
is controlled by somebody or other's laws (hey it been 30 years since
college) that govern diffusion and etc.

Yeah, I think i used retention and current capacity equivalently, when I
should have made the distinction.


Dave
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