I got 2.2 lbs off ebay for $18.00 free shipping... It made a night to day difference Mike...that coupled with the DE still in the filter, this water has NEVER looked better.... just follow the ascorbic acid treatment as posted in Metals and Stains Forum...CL needs to be ZERO/ PH at 7.0/ and PolyQuat is a must...
The Vit C would essentially work, but the strenghth is probably super low compared to the powdered Vit C...

Item number on Ebay was 261144196937 .... got it in 2 days after ordering...