"Michi Henning" wrote in message
...

Ah, OK, I'm with you now -- I agree. The KH is a constant for the purpose
of this discussion, and the pH is the result of the amount of CO2 in the
water,
that is, the CO2 is the *cause*, and the pH is the *effect*.

I agree that, if people think they can lower the pH to get more CO2, they
are
misguided. The *only* way to get more CO2 is to put CO2 into the tank.
Products that otherwise tinker with the pH to artificially lower it (such
as
"pH Down"
and similar) don't do a thing to the CO2 level. And, if such products are
used,
the
chart will indeed be way off.




yes, that is the point I was trying to make ;o)




Ah, yes :-) Actually, according to Krause, the equilibrium level is
closer to
0.5ppm.
But the precise figure is academic, I suspect, because 0.5ppm and 2-3ppm
are
very
nearly the same when it comes to growing plants: too little.

I have heard anywhere for .5ppm to 5ppm. The last one I read said they were
measuring 2-3ppm at equilibrium, so that is what I said. But like you said,
it's all acedemic, since it is too little for massive growth.


btw, I don't even have plants yet ;o)

I've been keeping fish for ~20 years, but never plants. But I have been
lurking here and other plant forums for the last few months trying to absorb
knowledge. And this co2 chart bugged me at first until I finally realized
that it only applied to systems using only co2 to change the ph, and not to
water using other buffers to lower the ph.


I am going to be planting my 75gallon tank today. No co2 as of yet
though, just a bunch of plants that supposedly don't require much co2 to
live well. We shall see. I have finally found a co2 distributor here that
sells to individuals, so I will be adding co2 in the next few weeks and go
from there.


--

Margolis
http://web.archive.org/web/200302152...qs/AGQ2FAQ.htm
http://www.unrealtower.org/faq