Frequently asked questions

Find on this page answers to common queries about The Geochemist's Workbench®.


When was The Geochemist's Workbench® first released?

The Geochemist's Workbench® was introduced in 1991 and since then has set the standard in geochemical modeling. More than 3300 licensed copies have been installed in 66 countries around the world.

Who is Aqueous Solutions?

The GWB software was developed originally by the students, staff, and faculty of the Hydrogeology Program at the University of Illinois. The development team moved to the University of Illinois Research Park and works under the name Aqueous Solutions LLC. The team is supported solely by end-user license fees.

How does GWB Student Edition differ from the Professional, Standard, and Essentials versions?

Our handy charts show the programs and features in each version. The academic upgrade page outlines the features of the various versions. Please visit the main GWB website for detailed information about the paid versions of the GWB.

What's new in GWB12?

GWB12 is a major advance in the modeling capability and user experience of the software package. Highlights in the new release include Phase2, the ultimate phase diagram generator; a generalized model of stable isotope fractionation; a partial pressure model; a unified rate model; stable isotope transport; presentation grade graphics, including razor sharp lines and artist-designed palette; open-source XML plot-format output; anion exchange; and much more. A must-have for every lab!


Am I eligible for a free download of GWB Student Edition?

To apply, you must be currently registered as a full-time degree-seeking undergraduate or graduate student at an accredited university offering degrees in geoscience. You’ll need a LinkedIn account to apply.

How do I create a LinkedIn profile?

Visit LinkedIn's homepage to create an account.

I’m a university professor that would like to use GWB Student Edition in my class. Am I eligible for an academic discount on GWB Professional, Standard, or Essentials?

Please see the academic page for qualifications.

I'm a postdoctoral fellow doing university research. Can I download GWB Student Edition?

Postdocs may be eligible for a 20% academic discount on GWB Professional, Standard, or Essentials. Please see the academic page for qualifications.

My GWB Student Edition license expired. Can I reapply?

Licenses last for up to a year, after which you will need to reapply so we can re-verify your credentials. We’ll contact you and remind you when it’s time to reapply.

How can I check the status of my GWB Student Edition application?

You can check the application page at any time to see the status of your application.

I applied for a free download of GWB Student Edition. Why haven’t I received a license yet?

If you haven't received your free download of The Geochemist's Workbench® within 2-3 business days, we are either having trouble verifying the academic status of your advisor or your advisor has not responded to the verification e-mail we sent out. Please verify that the contact information for your advisor is correct, then check whether the verification e-mail we sent went to your advisor’s spam folder.

I incorrectly entered my contact information, or that for my academic advisor. Can I submit another application?

You can cancel your submission by returning to the application page and clicking the cancel button. After you cancel your application you’ll be able to submit a new application.

My advisor is currently unable to check email. Can I designate a different academic official to verify my student status?

You can cancel your application and reapply, as described above.

Why was my application for GWB Student Edition denied?

An application might be denied if we were unable to verify your status as a full-time, degree-seeking student at an accredited university. You can reapply later if your student status changes.


Can I upgrade my copy of GWB Student Edition to the Standard or Professional version?

Yes, please visit the main GWB website or contact for a quote or an academic code.

How soon after I place an order will I receive the software?

You will be up and running within minutes. After you check out of our online store, you'll receive email containing a link for downloading the GWB installer, as well as an activation code. Install the software, enter the activation code, and you will be ready to go.

Can I try the software before I buy?

Yes. Please visit the main GWB website to request a demo copy.

How can I get a formal quote for purchasing a license, upgrade, or training?

Please request a quote from the main GWB website or contact

Am I eligible for an academic discount?

Please see the academic page for qualifications.

How can I get a multi-license discount?

Simply add copies to your shopping cart to receive the discount. Contact to request a discount on additional purchases made shortly after your original purchase.

Should I wait for the next release?

Even we don't know exactly when a new releases will be ready, but you can order with confidence. If you've purchased a license to the GWB within 60 days of a new release, contact us for a free upgrade.


What programs are included in each version of GWB?

Here's a handy chart that shows the programs included in each version, and what each program does.

What sources of thermodynamic data are available?

The default thermo dataset, thermo.tdat, compiled by Lawrence Livermore National Laboratories, as well as a number of other datasets are installed with the software. You can download any or all of the datasets from the thermo data page. You query the users' group about thermo datasets via the GWB Student Forum.

I overwrote a thermo dataset. How can I restore it?

You can download any of the datasets installed as part of the GWB from the thermo data page. You can as well find links to other sources of thermodynamic data there.

How does the GWB calculate activity coefficients?

By default GWB uses the "B-dot" model, an extended form of the Debye-Huckel equation, to calculate species activity coefficients. Where the ionic strength is high, you can calculate activity using the "Pitzer equations."

How does the GWB model sorption?

GWB can account for sorption onto surfaces using: the Kd approach; Freundlich or Langmuir isotherms; ion exchange; or the double layer model of surface complexation, with or without electrostatic effects.

Can I model more than one sorbing surface?

You can combine as many sorption datasets as you like, and you are free to mix, for example, Kd sorption with surface complexation reactions.

Can I mix water samples in GWB?

You can easily mix samples stored in a GSS spreadsheet. Or, upgrade to GWB Standard and use program React to simulate mixing processes. In this way, you can calculate pH buffering, the dilution of contaminants, the precipitation of minerals, or the energy available to microbial communties along geochemical gradients.

Can I construct models accounting for reaction kinetics?

Upgrade to GWB Standard or GWB Professional to include in any reaction or reactive transport model the kinetics of (1) mineral dissolution and precipitation, (2) formation and dissociation of complex species, (3) sorption and desorption, (4) redox transformation, including the effects of enzymes and catalysts, (5) microbial metabolism and growth, and (6) gas transfer.

Over what range of temperature can I apply the GWB?

The GWB programs operate within the temperature range of the thermo dataset currently loaded. The default thermodynamic dataset thermo.tdat contains log K entries compiled along the steam saturation curve from 0°C to 300°C.

Do I need to account for confining pressure that deviates from steam saturation?

You can use a thermo dataset compiled at the pressure of interest, but hydrothermal chemists not uncommonly assume the effects of confining pressure are small compared to the uncertainty in determining log Ks and activity coefficients. Note, however, that gas partial pressures are almost invariably significant. You account for the partial pressure of a coexisting gas by setting its fugacity.

Why do the charge imbalances I calculate with the GWB differ by a factor of two from the imbalances I compute by hand?

The GWB uses the calculation technique presented by Weight, W.D. (2008), Hydrology Field Manual, McGraw Hill, 751 p.
{charge balance = 100 * [((sum cations - sum anions) / (sum cations + sum anions)) / 2]}

Some people prefer to figure charge imbalance according to Zhu, C. and Anderson, G. (2002), Environmental Applications of Geochemical Modeling, Cambridge University Press, 284 p.
{charge balance = 100 * [(sum cations - sum anions) / (sum cations + sum anions)]}


On what versions of Windows does the GWB run?

GWB release 12 runs under Windows 10, 8 & 8.1, and 7.

I'm having trouble installing and running my copy of GWB. Whom can I contact for help?

For installation issues consult the GWB Student Forum or the LinkedIn group and, if necessary, post a query there.

Can I run the GWB on a Mac?

Many of our users have found success running GWB on a Mac using a dual boot configuration or Windows emulator such as Parallel Desktop.

How do I install and activate the GWB software?

When your application for GWB Student Edition is approved, you will receive a download link and an activation code. To get started, click the link and follow the installation prompts. After you’ve installed the software, go to the Windows Start menu and click on The Geochemist’s Workbench to launch the GWB dashboard. Move to the Support tab and click Activate GWB. In the space provided, enter your activation code and click Activate.

How do I move the GWB software to another computer?

First, return to the GWB activation utility on the computer which has the GWB activated. To do so, open the GWB dashboard and move to the Support tab then click Activate GWB. Next, select your activation code and click Deactivate. Finally, follow the steps to install and activate the software on a different machine. You will be able to move each license a limited number of times per year.

How can I receive help setting up or trouble-shooting my models?

Please post queries to the GWB Student Forum.

Can I use the GWB without an internet connection?

No, you will need an internet connection to activate the GWB Student Edition of the software.

Why do I receive the error “This activation code is already activated on as many computers as allowed”?

Each license of the GWB is limited to use on one machine at a time and must be deactivated before being activated on a new machine.

Documentation, training, and consulting

I just want to make a diagram. Can you show me how?

The tutorials page contains concise step-by-step instructions for making a variety of diagrams. The diagrams page holds a gallery of diagrams produced using GWB Student Edition. Click on the icon below a diagram to launch the corresponding GWB app, pre-configured to compute that diagram.

Please visit the main GWB website for more tutorials and to browse the movies and additional diagrams you can produce when you model reaction paths and reactive transport with GWB Standard or GWB Professional.

Where can I find fully-worked examples of GWB runs?

Open pdf copies of the User's Guides from the Support tab of the GWB Dashboard, the Help tab of any GWB app, or from the documentation page. Consult the Geochemical and Biogeochemical Reaction Modeling text for many more examples. And check out the GWB Online Academy, a self-guided course in geochemical and reactive transport modeling.

How can I get hardcopies of the User's Guides?

You can purchase hardcopy documentation sets from the main GWB website. Or download pdf copies of the guides and cover art, and let your favorite copy shop print and bind the manuals for you.

I'd like to get up and running quickly. Can I arrange one-on-one training?

Consider traveling to our headquarters for Quick Start training. One or two people receive one day of introductory training for a fixed price. Visit our workshops page for details.

Where can I learn about the theory and practice of reaction modeling?

The textbook Geochemical and Biogeochemical Reaction Modeling, written by the principal author of GWB and published by Cambridge University Press, is available in hardback, paperback, and Kindle editions from Cambridge or

Do you offer short courses or workshops?

Yes, we present workshops offering hands-on training around the world. Our offerings include Problem Solving with The Geochemist's Workbench® and Reactive Transport Modeling in Geochemical Systems. See our workshops page for details, or contact to check on planned offerings or suggest a location.

Do you offer on-site training?

We can save your organization time and money with on-site training courses. Contact to request more information.

What about online training?

The GWB Online Academy offers self-paced online training in Geochemical Reaction Modeling and Reactive Transport Modeling. Arrive as a beginner, leave an expert!


Is Aqueous Solutions hiring?

Aqueous Solutions is always interested in seeing the resumes of extremely talented application programmers and geochemical modelers.