On Mon, 07 Jul 2003 15:19:15 GMT, "Linda" wrote:

Do all planted aquariums have to have CO2 for the plants to grow?

Yes and no.

All plants use CO2 for photosynthesis.

Some aquarium plants can obtain the needed carbon from carbonates, but
the process is not efficient, and only a few plants can do it.

But, this doesn't mean you must inject CO2, since there will be some
amount of CO2 dissolving into the water from the air.

With higher light levels, plants will need far more CO2 than the
3-4ppm present without CO2 injection. So in those cases, CO2
injection is necessary. But even at lower light levels, CO2
injection will improve plant growth.



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