Is it ok to give your toddler (2 years) sparkling water? What's too much?

Fizzy water has a low pH and high titratable acidity.... all adds up to acid erosion of the teeth. Decidous teeth (ie the baby ones) are more vulnerable to erosion as the enamel is thinner. I would avoid fizzy drinks on a regular basis and fruit shoots for that matter. Fruit juice itself once a day with a meal would be ok.