Perhaps a cheaper source of ascorbic acid could be found, as opposed to a health food store. The 99 cent store here has 100, 100mg tabs for 99 cents. Tax will raise the price to $1.07. This would allow you to neutralize 250+ gallons for $1.07.
Regards,
JS
Nearly on-par with prime's pricing when buying the smallest bottle. Larger bottles may even the gap and perhaps make prime cheaper. :/