Dissolved salts are known to affect a variety of phenomena in solution ranging from protein solubility to enzyme activity to colloidal stability, and the Hofmeister series has long been recognized as a qualitative ranking of these effects. Despite its age, an understanding of the physical basis of Hofmeister effects is far from complete and remains an active area of study. We have previously observed that Hofmeister effects of sodium salts on protein deactivation strongly correlate with the Jones-Dole B-viscosity coefficient of the anion of chaotropic salts (B < 0) and show little variation in solutions of kosmotropic salts (B > 0). As B-viscosity coefficients are indicative of ion hydration, this observation indicates that ion hydration strongly influences a salt's effect on a protein and that B-viscosity coefficients may be useful for predicting salt effects on protein deactivation. Since protein stability plays an important role in protein misfolding diseases, we test the influence of ion hydration on the aggregation and fibril formation rates of aggregation-prone proteins known to form amyloid-beta fibrils using the yeast prion Sup35 as a model protein. As part of this study, we have discovered that a previously published dye-binding assay commonly used to track fibril formation is frequently wrongly applied and less accurate when applied to other proteins. Development of an improved assay for Sup 35 fibril formation and its use to quantify salt effects on fibril formation kinetics will be presented.