[hugodahl]

All three manufactured/retail products listed also contain a non-insignificant amount of potassium, particularly the Pedialyte, to which the homemade solution matches best. Is the value added by potassium minimal enough to not include it? Or is availability in a common household more of an issue?

I have seen in stores sodium-free salt, and reduced-sodium salt, which both substitute potassium for the "missing" sodium, which can be a source of potassium if the added benefit is worthwhile.