Warning: If the quantity of
a medium in a Cell is not constant (and you are running at Medium or High
Precision), the concentrations are computed based on an effective amount (a
weighted average over the timestep). This can result in errors in the computed
concentrations (and hence the mass flux rates) if the quantity is changing
rapidly over a timestep. As a general rule, the errors will be
insignificant as long as the quantity changes by less than 10% over a
timestep. If this is not the case, you should reduce the timestep to
ensure that it is.
Warning:
If the quantity of a medium in a Cell goes completely to zero, some mass will be
left behind in the Cell (until media is added to the Cell again). Although this
may actually be physically realistic in some cases (e.g., outflow due to
evaporation, and hence precipitation of the mass), in other cases it is
not. The magnitude of the error can be reduced by reducing the timestep as
the Cell approaches being empty.
Note: A medium that has zero
volume (fluids) or mass (solids) cannot have a species concentration. Any mass in the
Cell will either partition into other Fluids (if present) or in the absence of
other Fluids into which the mass can partition, precipitate out onto any Solids
present in the Cell (proportional to the mass of each Solid) even if no solubility limit is
specified.