I have used metal magic by proteam. They are all bascially the same. Jack's Magic is good, Sequasol and Metal Free too. The one thing is not to shock the pool until all of the metal is sequestered. Most stain removal products say not to shock for at least 2 weeks. I usually put a little more sequestering agent in again in about 7 days after the treatment. The important thing is to keep your ph down at about 7 to 7.3 while you are adding chlorine, and add the chlorine slowly, a couple of ppms a day till you get it to shock if you need to get it to shock. If there is no combined chlorine, there is no reason to take it to shock. Just keep the chlorine at the low end of the "best guess chart" - but you must test frequently so that you don't let it get too low and get an algae bloom.