I used metal magic - while it wasn't exactly magical about taking off some tough old iron stains it did further lighten them - nothing so far has completely removed them though so it worked as well as Ascorbic Acid and better than Oxalic. One thing I do notice though is that I had little granules on the bottom after a couple of days. They were rust colored.. so possibly, and just maybe it did cause the iron I have to drop out of the water. I'm still seeing a bit of it each day and I'm cleaning it out each day. It looks like rust colored sand. It did take me a week to get my water clear again after the metal magic treatment, so I didn't post before now about results because I really couldn't tell about the stains. They are still there a bit, but lighter than ever. I think 1 more AA treatment may do the trick.