seltzer may have been a brand name?

tonic= club soda + quinine

The British found out that quinine could help with malaria and added it to water. Then added gin so troops would drink it. The amounts used today aren't enough for protection from malaria.

Seltzer and club soda are carbonated water. Seltzer is supposed to be just plain. Club soda can have mineral enhancements.

Here is a link. Way too many adds to make a good read.

https://savorysuitcase.com/seltzer-vs-club-soda/

I don’t drink but if I end up in a bar, it’s my option. With a twist of lemon.

Still a couple of bottlers doing it the old fashion way in Brooklyn and delivery is possible

bones. I've been working like a dog lifting weights to rebuild bone after an osteoporosis diagnosis, but I also had a habit of drinking club soda like water.

Tonic water is carbonated water with quinine added
Seltzer and sparkling water are usually the same - carbonated fizz added.
All fizzy carbonated drinks are acidic in nature and that’s what affects bone density in a negative way.