Jump to content
Geochemist's Workbench Support Forum

Did Not Converge Error - Charge Balance


 Share

Recommended Posts

Hello!

 

I am struggling to understand my results from Spec8. I have 10 samples and am trying to get charge balances and Saturation Indices.

 

All the chemistry is quite similar between samples, however I only get results from 3 out of 10 of the samples. For the rest I get

 

N-R didn't converge after 999 its., maximum residual = 0.451, Xi = 0.0000
I attached my spread sheet below in hopes that someone smarter than me could figure out where I am going wrong!!
Thanks so much!!
Shona
Link to comment
Share on other sites

Hello Shona,

 

Thank you for sharing your spreadsheet. It’s hard to tell what’s wrong. I noticed that you’ve described your samples with a mix of basis entries (these are constraints on the calculation) and user-defined analytes like P, Si, and Sb (these have no effect on the calculation). As a result, the program has an incomplete understanding of the systems’ true chemistry. Perhaps this is the source of the error you’re encountering. I recommend completely describing your fluid in terms of basis entries and double-checking that all of your values and chemical units are correct.

 

You can specify the masses of basis entries like HPO4—and SiO2(aq) in terms of their elemental equivalents (i.e. HPO4-- as P and SiO2(aq) as Si) so you don’t have to do any extra work to get the spreadsheet in a form compatible with your water analyses from the lab. As for the Sb, GWB’s default thermo dataset, thermo.tdat, doesn’t include that element so you won’t find it in the list of basis entries in GSS. Other datasets included with the software, like thermo.com.V8.R6+.tdat, do. You can try loading that thermo dataset instead, or you can easily modify an existing dataset, either by copying entries from one thermo dataset to another or simply adding information directly from the literature.

 

For more information on thermo datasets, see the TEdit section in the GWB Essentials Guide. You can also view tutorials on how to edit thermo datasets here. Once you pick a suitable dataset, you can load it into GSS by going to File -> Open -> Thermo Data… and browsing for the file.

 

Kind regards,

 

Katelyn

Aqueous Solutions LLC

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...