On Fri, 27 Sep 2002 16:38:04 GMT, "Corby Cox"
wrote:
Should I rig a timer to shut off CO2 at night? Plants aren't getting any
use out of it (I think), but it stabilizes the pH between 6.8 and 6.9, which
is where I wanna be. Concerned about Otos and other fish sensitive to large
pH swings. No CO2 at night would probably mean 6.8-6.9 during day, and
7.3-7.5 at night. With CO2, it's always between 6.8 and 6.9.

If it's stable around 6.8 or 6.9, then obviously you are not getting a
buildup of CO2 at night. My tank operates this way, likely due to
some CO2 loss from my wet/dry filter, and due to the amount of surface
movement I've got.

I'd leave it going all the time. The only possible downside is that
you are wasting a little CO2. But CO2 is cheap.

Why expose the fish to an un-needed pH swing. Plus, with the CO2
being shut off at night, the CO2 level in the water would be low,
slowing down the plants photosynthesis once the lights come on until
the CO2 level built back up all the way.


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