We’ll start with the best sparkling water; Sparking, mineral water. The effervescence comes from naturally-occurring mineral salts. The principal ions are calcium, magnesium, sodium bicarbonate and sulfur compounds. These electrolytes boost cellular hydration and create a more potentially positive, hydration effect.
A word about the magnesium (Mg) content; 75% of us in the US are deficient in this mineral 50% of Mg in this sparkling water is readily absorbed. One (1) liter (33 oz.) would provide approximately 29% of the daily value for this mineral, about 108 mg. And the pH averages 5.7 (Optimal, healthy pH is 7.2).
Artificial carbonation is the hallmark of club soda and seltzer. Club soda is infused with Potassium sulfate and sodium phosphate, sulfate and bicarbonate. This gives it a slight salty, drinkable quality, but it is considerably acidic. Seltzer does not contain added minerals, which gives it a “truer” water taste and is the preferred cocktail mixer. Tonic? This is a soda! There are 30 carbohydrates and 116 calories in 12 oz. and no appreciable nutrients.
Clearly, sparkling mineral water and pure water are the best hydrators.
https://www.medicalnewstoday.com/articles/324910.php
https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
https://www.fda.gov/consumers/consumer-updates/bottled-water-everywhere-keeping-it-safe