Nestor 10 wrote:
youhavereachedadam wrote in message
oups.com...
I have a question about CO2 as well so I will throw it in here. If I
had a plant-only tank, say an aqua garden or a growing tank for plants
I want to sell, is there such a thing as too much CO2?...
"Elaine T" responded in message
om...
Yep. You will suffocate your fish with too much CO2. I forget
the amount that kills them, but it's quite possble to do.
Elaine might have missed this part in her response as there are no fish
involved. The numbers that she can't remember for fish (only since it was
brought up) is about 40 ppm. Such a concentration does not suffocate the
fish, instead severely limiting or even prohibiting the release of CO2 from
their bloodstreams in respiration. If the bloodstream cannot release its CO2
then acidosis occurs within the body, triggering detrimental systemic
responses.
Ah. I did miss the plants only bit. R.a.f.m is usually a fish NG. I'd
have probably picked it up if I'd been reading r.a.f.p instead. Thanks
for reminding me of the 40 ppm limit - I generally stay below 30 ppm for
safety when I'm running CO2.
As for my use of the word "suffocate", if you want to nitpick, high CO2
and the resultant acidosis interferes with the ability of hemoglobin to
carry oxygen. Hemoglobin undergoes an allosteric change when the blood
pH rises in the gills/lungs from release of CO2. That structural change
causes it to become a more efficient oxygen carrier. Without the
release of CO2, the blood stays acidic, hemoglobin functions less
efficiently, and the animal becomes oxygen deprived and (among other
problems) suffocates.
Another problem with extremely high CO2 is that the partial pressure of
O2 can be reduced, particularly in warm water. Lowered 02 exascerbates
the problems caused by excess CO2, further contributing to "suffocation."
youhavereachedadam continues with...
I know that adding lots of CO2 will lower the Ph, so there is obviously
an upper limit to how much CO2 could be injected...
The amount that will dissolve in the water is dependent on many factors, and
the combination of all of them will most likely _not_ allow the
concentration in a tank to reach levels that will prove harmful to plants
unless you were to completely seal the tank. NetMax is correct in his
assumption that at some level of injection you will reach a point of
diminishing returns.
Concentrations of 30 - 40 ppm have been suggested as good for plants by such
as Dennerle, Tropika and members of the Aquatic Gardeners Association.
I have always wondered whether photosynthesis becomes light limited
again 30-40 ppm CO2. I'm always fascinated at how fast my submerged
pond plants grow under the simple conditions of sunlight, nitrogen from
the goldfish, and atmospheric CO2.
What about piping CO2 to the base of the plants and bubbling the
gas up through the leaves?...
Speaking of the AGA, their mailing list (archived at
http://fins.actwin.com/aquatic-plants/ ) recently discussed the pros and
cons of CO2 "misting" as it affects plant growth, with emperical evidence
pointing to the PRO side of the argument. My own experience with misting
lies with using the filter's impellor to not only dissolve CO2 into the
water but provide a fine mist of undissolved bubbles (I tend to yeast
reactors to provide a more - than - ample supply of the gas) with fantastic
results over the last few years.
The AGA mailing list is an outstanding resource. The subscription
website is on
http://www.actwin.com/mailman/listinfo/aquatic-plants. I
only lurk there - I can't afford the snazzy equipment to really comment
on much.
Any mad scientist ideas out there? I have a 10g tank sitting in my
garage just waiting for a haribrained scheme.
With a 10- Gallon tank and optimal growth conditions, you may as well sell
your excess - you'll certainly be pruning often enough ;-) ...
--
Elaine T __
http://eethomp.com/fish.html '__
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