If you change the author of the property equation in the Electrolyte Properties Page (to Røstum, for instance) AlPrg draws the corresponding Electrolyte Properties Diagrams.
A completely grey icon graph (or property diagram) means that the electrolyte property does not depend on this parameter.
The equation of
Røstum for the liquidus
temperature contains no dependence on magnesium and potassium fluoride.
A partially grey region in the graphs or diagram means that AlPrg could not determine the
value or the value was out of the limits.
In the region of the grey area of the aluminum fluoride graphs and diagram AlPrg has obviously problems to evaluate the cosine in the equation of Peterson.