Last year, I continuously battled copper stains. The ascorbic acid treatment worked, but the Metal Free or Sequestering Agents I used didn't seem to do much about keeping the stains away.
Basically, I think I have an unusually high copper problem due to an exchange heater that corroded and spilled lots of copper into the water.
I heard Jack's Magic was pretty good? Does anyone have any experience they can share with a product that works? I want to be VERY proactive about stains this year.