The three properties that you enter for a Fluid are "passed through" the element and become outputs which you can then link to other elements.
You can save these results by clicking Final Values and/or Time Histories. Checking one of these causes all three outputs to be saved as results. If you wish to save only one or two of these as results, you can use the context menu of the output (accessed via a right-click) in the browser An alternative view of a GoldSim model, in which elements are displayed in a tree, and organized either hierarchically, or by type. to turn on or off one or more of the three outputs. In this case, the checkbox in the dialog will become gray (indicating that some of the results will be saved).
The display units The units (e.g., m, g, $/day) in which an output is displayed within GoldSim. for the Reference Diffusivity output (and Solubilities if they are specified) are defined immediately to the right of the input field (the Relative Diffusivities and Partition Coefficients The ratio of the species’ concentration in a medium to its concentration in the Reference Fluid at equilibrium. Partition coefficients are inputs to Solid and Fluid elements. are dimensionless, and hence do not have display units).