On Tue, 18 May 2004 18:38:02 -0700, "Sir Douglas Cook"
wrote:

Co2 pump are so easy to make why would anyone pay for one???????????????

Yeast CO2 systems do provide as stable a source of CO2. Additionally,
they require much more time and effort. With a compressed gas CO2
system, you can set it, and not touch it for a year or more. The
price of yeast and sugar isn't free. I pay $10.00 for over a year
worth of CO2 for my 75g tank. To do that with a yeast system would
require several 2L bottles, and constant work mixing and changing
them.

your undergravel filter where there is lots of surface area for the gas to
exchange.

The buildup of CO2 in the UGF would probably negatively effect the
bacteria that are critical for proper UGF operation.

care, if at all. Remember that high CO2 levels may reduce the oxygen uptake
of the water and lead to a risk of hypoxia in the fish, especially if the

Completely false at levels encountered in our aquariums. CO2 levels
elevated to the levels used for planted aquaria (40ppm max) will not
prevent any absorption of O2.

Additionally, when used correctly in a planted aquarium, with high
lighting, lots of plants, and CO2 injection, the plants photosynthesis
rate will be high enough to drive the O2 level over 100% during the
day. This is a cause of the "pearling" often seen in a healthy
planted tank. O2 bubbles are released into the water, because the
water cannot absorb any more.

In regular non-planted aquarium, using airstones or powerheads for
water movement/aeration, typical O2 levels are around 75%. In a
health CO2 injected planted tank, the O2 levels are over 100% during
the day, and during the night, only fall to 80% or so.

dioxide, making the CO2 injection a rather pointless exercise! CO2 injection
should always be turned off at night - When the plants do not need it."

Tom Barr recently published some university studies that showed that
algae is better able to handle fluxuating CO2 levels better than
higher plants. So by constantly having the CO2 level rise and fall,
you are giving the algae a slight advantage over the plants.

The only possible reason I see to turn off CO2 at night is to save the
cost of the CO2. But when I pay just $10.00 for more than a year, I
can't see adding the cost of a solenoid and timer to switch the CO2 on
and off. It would take decades to make up the cost.


Chuck Gadd
http://www.csd.net/~cgadd/aqua