With The Blue Stuff, do you have to lower chlorine, etc., before use?

They have a very specific list of parameters for stain treatment. Here is a link to the one for Blue Stuff. http://www.jacksmagic.com/pdfs/3-Simple-Steps.pdf

I have a salt pool . Is the purple stuff a stain remover? Do you have to lower the chlorine?

I recommend this VERY highly for salt systems. It also removed stains. I did NOT have to lower the Chlorine.I recently had a salt water system installed and just switched to Purple Stuff. from the Blue Stuff that I used before. It worked GREAT! The package says that it is for Salt systems and it is. I used 2 quarts in a 29,000 pool, less than the 3 quarts that the bottle recommends. My back pressure went up about 4 - 6 lbs in less than 24 hours, meaning a lot of "stuff" was taken out of my pool and put into the filter, where it belongs. (Be prepared to back flush after you use it for the first time) It DID remove stains in my pool. While not very bad stains, they were noticeable ...they are now gone. FYI, I have a 25 year old concrete pool that has been Fibertech lined, meaning Fibertech technicians coated my badly worn concrete with a new fiberglass lining. (worked great!) I would guess that it would work on a concrete pool as well. I will probably use Purple Stuff at least 2 - 3 times a year. Leslie's used to carry the Jack's Magic line but discontinued it several years ago, Big MISTAKE on Leslie's part, and another reason why I don't go their anymore. I am obviously sold on Jack's Magic's entire product line. FYI, they also have VERY helpful USA based customer service reps on the phone line. I called them before buying Purple Stuff with some questions. They can answer any questions you may have.

I have a high copper content in my pool water. Will this lower it?

I have a fiberglass in-ground pool. I am not sure if I have iron or copper in my water, but I get staining along the waterline from it. The Blue Stuff makes it go away overnight when I use it.

Is there another way to remove the metals from the water, once you remove stains, than having to clean the filter?

If you found the source of the metal and removed it, there are products that you put in the skimmer. After the stain lifter is added and you see the stains disappearing, I have used a product called “CULATOR” that you put in your skimmer and should catch all the metal. It last for 30 days and as long as you removed the source, this should take care of the problem. Once the metal is gone for good, I would recommend changing your sand in your filter or at the very least, use a sand cleaner. If the stains keep returning, then the source is still in play. Heaters, lights and sometimes screws can be a source and you would be surprised the amount of stains can be produced by a rusty screw. Hope this helps.