I replied to similar comment above. I certainly did not take great pains to accurately measure hydration status. But I did eye ball my urine output and it seem

I replied to similar comment above. I certainly did not take great pains to accurately measure hydration status. But I did eye ball my urine output and it seems that seltzer really ups it, a lot more than tap water or even a "normal" [not high abv] beer like coors. Maybe my body is uniquely sensitive to highly carbonated liquids. Maybe it's all in my head. But I think it's real.