I used to use leslies all the time and it does work well but gets expensive, as I have to remove stain weekly. Every time I raise the chlorine it comes back.

I used to do this and it took about 3 days to do it (leslie's method)
1) Lower the chlorine (about $10 for the bottle)
2) Use metal free (I think $20)
3) run for a couple days
4) Back flush
5) Destain using Leslies Ascorbix acid ($40 for 2 pounds)
6) Raise the chlorine

But I have found that the ascorbic acid is a contact agent, and a cheaper way to do this is
1) Order ascorbic acid from MSM MSM (Half the price 12.50 a pound as opposed to leslies $20 for a pound)
http://www.msm-msm.com/faq.html
2) Turn off the pump for 1 hour
3) Drizzle very small amounts of the ascorbic acid around the edge of the pool (about .75 pounds max for a 15000 gal pool)
4) Let ascorbic acid float down the sides of the pool
5) Let the pool sit for 4 hours, then turn the pump on. The next morning its perfect.



I have had this problem for 3 years and at the beginning of every pool season I have spent countless dollars lowering the chlorine, using metal free, and using ascorbic acid only to have it come back even when the tests at the pool store say there is no metal in my pool.

The method above costs me about $10.00 a week