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question about PHREEQC



Hello Dr. Parkhurst, 

I'm not certain if you are still answering the questions about PHREEQC, and
don't expect that this question will have significance to anyone other than
myself, but I have read all the questions on the PhreeqcI webpage and have
yet another.  

I have been using the 2.4.2 Alpha version of Phreeqc Interactive and
selecting the wateq4f database because I am interested in allophane, and
the phreeqc database does not include allophane.  Here's the strange thing:
if I put the same data into PHREEQC (with the wateq4f database selected) as
were put into WATEQ, I will get allophane as supersaturated in the WATEQ
results, but allophane is not even listed in the PHREEQC phase results.
Some of the other mineral phase log IAP values are dead on, most are off a
little and others are off more, with no clear pattern in the results (so I
think I am entering them all correctly).  I would expect that with the same
input and same databases, the log IAP values would be a little off, but
that the same mineral phases would appear in the output.  Is this an
incorrect assumption?   

I understand that the easiest thing for me to do is to use WATEQ, but I
have never used it (I got the run output from someone else) and prefer the
comfort of PHREEQC. 


Any help would be greatly appreciated, 

Caroline





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