Vitamin C (Ascorbic acid) is an antioxidant,

Ascorbic acid binds to the Chlorine in tap water.

Product idea: an ascorbic acid water treatment device for garden hose water

Remembered this because of this video about hot plasma water treatment yielding 30% higher biomass;

"This Brawndo Plasma Thermos Makes What Plants Crave" (2026) https://news.ycombinator.com/item?id=48790001