Software that Clarifies, not Confounds
In developing MINEQL+, it was important that everything be as visual as possible. If you download some of the freeware models that are available, you will find they often obscure the assumptions that go into running the calculation. It's great if a program has a state-of-the-art thermodynamic database, but why should you leave it to faith that it is being applied correctly? In MINEQL+, all chemical reaction data is visible. MINEQL+ has a Tableau tool that allows you to add, delete, edit or just review all reaction data prior to running a calculation. This is a very powerful feature. It turns MINEQL+ from a model (where you accept other people's assumptions) to a modeling system (where you have full control of the assumptions).
The concept of visualization was also important when dealing with output. MINEQL+ allows you to plot any chemical species (up to 10 at a time) versus any independent variable (such as pH). So you can easily generate logC-pH diagrams, alpha-distributions (ion fractions), solubility plots, titration curves, or sensitivity plots.
You can browse this website to see all of MINEQL+'s features. The point I'd like you to take away here is that good software should help you focus on the subject it addresses (in our case, chemical equilibrium) and not provide a technological impediment. All too often, we as human beings force ourselves to adapt to technology that is poorly designed or ill-conceived.
MINEQL+ has been available on the web since 1995 and in that time it has been used in over 500 colleges and universities to teach courses in aquatic chemistry, soil chemistry, chemical cycling, and geochemistry.
If you are serious about performing chemical equilibrium calculations, either as a teaching tool or in research, please consider purchasing MINEQL+. It will practically make aquatic chemistry a pleasure.