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Re:CO2 by breathing

>Steve Pushak wrote:

>How many tanks can you fertilize with a garbage bag full of exhaled air?
>How frequently do you do this? I presume that you are using glass covers
>on these tanks to retain the CO2 atmosphere? Do these tanks have any
>water circulation of any kind in them? I've always been concerned about
>blue green cyanobacteria if there is no water circulation at all
>especially with a newly set-up soil tank. Do you ever have problems with
>BGA and how do you deal with it in these small tanks?

The method was written up in The Aquatic Gardener 4(3) and TAG 4(4), but
that was a long time ago.  I can do three 15 gallon tanks or one 75 gal
with one bag.  With the tanks covered tightly with glass, it lasts about 2
days, and then the rate of bubble production starts to drop.  I don't have
any kind of water circulation at all and almost never get bluegreen algae
take-overs.  I don't think that CO2 additions encourage or discourage
bluegreen algae.  If the BGA gets bad, I just turn off the lights and wait
until the snails eat it up.  In poor light the algae becomes palatable for
ramshorn or pond snails (or guppies) and they finish it up in a week or so.

This method of delivering CO2 is what I think of as REALLY DIY CO2, and,
compared to a yeast culture, a person really cranks it out.  Just resting,
an adult is producing the energy equivalent of a 100 watt bulb.  The CO2 is
a lot more convenient to diliver if you have the air stones and air tubing
for the tanks set up permanently and you just attach the bag of exhaled air
to the pump and turn it on with a timer set to about 40 minutes, which is,
for me, about the length of time it takes for the pump to empty the bag.
The pump for delivering the exhaled air is in a small bag with a hole cut
in the corner, and I stick the tube from the air bag into the hole and tie
it on tight with a rubber band.

Ken Cova wrote:

>.....I've noticed that if I fill my CO2 reactor (two upturned Rubbermaid
>containers in the sump) by blowing through an air line, my tank PH readings
>are lower than when I run with yeast generators.  Is yeast CO2 less
>concentrated than "human" CO2?

Not necessarily.   Exhaled air contains roughly 3.5% CO2.  I don't know
what the percentage is in the yeast CO2 reactors; it could be over 50%, but
the amount in the tank is due to the rate that the mix gets bubbled into
the tank.  If you collected all the gas from a yeast reactor and pumped it
into the tank with an air pump, you might get too much CO2 in and kill the
fish.  Exhaled air, on the other hand seems pretty safe.  I have never seen
it cause distress in guppies or zebra danios, which is all the fish I have.

Paul Krombholz,  where our month-long drought was broken in dramatic
fashion yesterday and today.