Re: Co2 Levels

From: RicCooney at aol_com
Date: Mon, 25 Nov 1996 10:25:37 -0500

> The optimum Aquarium lists CO2 levels as a function of KH and pH.  In
> my tank with a pH of 6.8 and a KH of 4.48 (80ppm x .056) I should have
> a co2 level of ~18mg/l which I assume is the same as ppm.

Yes, ppm and mg/l are the same for our purposes. 

> What are the adverse levels. I am now reading 45ppm and have read as
> low as 5ppm. When I saw that the level had risen to 15ppm, I
> disconnected my yeast co2 bottle overnight. The next morning I
> reconnected it and after about 2hrs I got the 45ppm reading.

There are differing opinions of maximum safe levels, but it is
generally agreed that less than 30 ppm is safe.

I'm quite surprised that you see such large CO2/pH swings.  Are you
sure that your "KH" measurement is really carbonate hardness (actually
alkalinity as measured by most test kits) and not general hardness or
total hardness (calcium hardness)?  Calcium hardness does not affect
pH and does not buffer the water.  You can have high calcium hardness
yet have very low carbonate hardness.  The charts are based on carbonate