Question: what is the difference between sodium metabisulfite and potassium metabisulphite?
Answer: Potassium metabisulfite is slightly stronger than sodium metabisulfite by volume—17% stronger—but this is not enough to be taken into account if you are only making 5 or 10 gallons of wine at a time. With either we recommend the same dosage. ... Campden tablets are nothing more than potassium metabisulfite in tablet form.