Re: Editing PHREEQC databases (fwd)

["David L Parkhurst" <dlpark@xxxxxxxx>]

> My apologies for bugging you about this, but I am having problems
editing the PHREEQC database and the User's Manual doesn't offer any
information.

I think there is a lot of information in the User's Manual ;).

> Two problems that I've encountered:

> 1)  I changed the equilibrium constant for Hfo_wH2AsO3 in Wateq4f and
saved the edited version to a different file name, as a "formatted text
(space delimited)" file.  No other format seems to run.  What is the
format of the original file?  I noticed that the edited version is about
50% bigger.

The original file and all input files for PHREEQC are white-space delimited
(tabs and/or spaces) ascii text files. You appear to be running Word or
some other text processor, and I'm not sure what it is doing to the file,
but it appears not to be good. You might try WordPad instead. PhreeqcI is
an interface that lets you enter and modify phreeqc input (or database)
files, which you may want to try
(https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc).

> 2)  When I changed the equilibrium constant back to what it was in the
original version (for Hfo_wH2AsO3, the value is 5.41) and run the same
input file, I get a different result than when I used the original
(unedited) database?.  Any ideas as to why this is happening?!?

No, I don't know what has happened, but all that is necessary is to include
a SURFACE_SPECIES data block in your input file that redefines the one
species Hfo_wH2AsO3.

      SURFACE_SPECIES
      Hfo_wOH + H3AsO3 = Hfo_wH2AsO3 + H2O
      log_k       new_log_K_Here

You can also change the database file as you have tried, you just have to
make sure you use the new database file. In batch mode, the database file
is the third argument in invoking PHREEQC. With PhreeqcI, this is done
through Properties in the File menu.

If you really want to know what you did, you can send the input, database,
and output files that you used and I'll take a look.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225