Re: CO2/pH

> From: krandall at world_std.com (Karen A Randall)
> Subject: Plants, CO2/O2 etc.
> I have also noted that 
> without any addjustment to my CO2 flow, the pH in my tanks only 
> varies by about .2 during a 24 hour period.  I often wondered why 
> the pH didn't drop more if CO2 continued to be pumped into the 
> tank, and the plants stopped using it.  
	A pH change of 0.2 implies a change in the CO2 concentration
of a _factor_ of 1.58.  This could involve an absolute change that is
quite large if you have a CO2 concentration that is in the range one
usually sees when CO2 addition is being used.
	(log(1.58)  =  0.2)

Paul Sears      Ottawa, Canada