On Fri, 22 Nov 2002 10:17:06 -0800, Dave Millman
wrote:

I was asked this question, and I'm not certain of the answer:

In a NON-injected plant tank, will diffusion of atmospheric CO2 keep up
with CO2 usage by plants, or is there a possibility that CO2 will get
depleted during the day, thus driving pH up?

In a non-injected plant tank, with good aeration, the level will
remain at a fairly stable 3-4ppm.

In a non-injected plant tank without good aeration, then it is VERY
common for the plants to consume all of the CO2 in the water, driving
the pH up to extremely high levels.



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