On 19 May 2004 08:57:56 -0700, (Giancarlo Podio)
wrote:

In my experience, unless you are keeping a low KH there is really no
need to turn CO2 off at night. In most tanks, the biggest loss of CO2
is not presented by the plants, it's from gas exchange, and this
doesn't stop at night.

I've seen exactly the same thing.

and a PH controller would be wonderful in those situations, but with a
KH of around 3-4 or higher you shouldn't have any problems with PH
swings during the night from CO2.

In fact, I've measured a larger pH swing when turning off CO2 at
night.


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