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Re: CO2 and buffering

Rich writes:

> It seems that the buffering capacity is the issue.  The water measures a
>  Carbonate hardness of 40ppm with the LeMotte test kit which I equated to a 
> dCH
>  = 5.06.
>  I just recently (two days ago) recalibrated the pH meter.  
>  I think that the water's buffering ability is low, but it seems difficult
>  stabilize.  
Carbonate hardness of 40 ppm is a more than adequate buffering capacity.  It
is possible that the water out of your tap has zero dissolved CO2.  Natural
levels of CO2 in the water will push pH down by .2 or so anyway.  So it weems
to me you should ldt a bucket of water stand overnight and see if what your
fancy pH meters reads in the morning.  It might just be that your tap water
has a pH so low that you cannot effectively use a meter set at 6.1 for
controlling the injection system.  You just have water that is soft and
acidic.  You're asking the controlling device to inject CO2 until the pH
reaches 6.1 and you're starting at 6.2.  There just may not be enough of a
difference for the system to function.

Bob Dixon