What is the difference between club soda and seltzer water?
Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
Seltzer water is simply regular water with CO2 dissolved into it by pressure, (it creates a weak acid called carbonic acid) where as club soda is carbonated along with some alkaline salts such as sodium bi carbonate added along to alter the acidity due to the carbonic acid.
Take home message about the difference: club soda has sodium (negligible amounts though) , whereas seltzer does not.