Adding a note: salts: Sodium and Potassium Chloride -- not pure sodium! they're chloride salts.

Also, for rehydration, REI sells rehydration salts, but I think those have some sugar too.

Adding an educational note: salts are compound molecules, such as sodium and potassium chloride, not pure sodium! They're chloride salts.

For rehydration, REI sells rehydration salts, but I think those have some sugar too.