I am a newbie and just successfully completed the AA treatment for iron stains that had built up over the last 2-3 years; I always attributed the stains to the neighbors' two oak trees that almost overhang into my pool. If you have oaks, you know what I am dealing with. I have a salt pool with a salt generator (swg) and after I completed my AA treatment, i used Jacks Purple stuff as the sequestrant. I have no idea what this stuff is but my pool looks great and it helps keep it 100% stain free. In my case, i added about 150% more of the Jack's than I needed to help keep stains from returning; i figured more was better with this stuff and since i know i have the phosphates anyways with the oaks, oh well.
From what i can gather, phosphates are a non issue IF you keep your cl in line with your CYA. You haven't been read the riot act yet but until you post your numbers, the advice here is going to be limited to what your specific pool parameters are. First thing i did was buy my taylor k2006 and i love this tester and knowing my pool parameters has made the info on this site invaluable to the way my pool looks now.
In my case, I have a serious CYA level of 150 so I have to keep my chlorine up and at the same time balance it so it's not too high to redeposit the stains. Jacks purple stuff has phosphates but as chem geek has pointed our over and over in his posts, it's a non-issue if you keep your cl in line, phospates can't feed algae if you have chlorine in the pool. yes Jack's is more money, but hey, isn't that what a pool is for, to throw money into?
Finally, as to your re-staining issue, that wasn't my issue. After the AA, mine was cloudy water. This lasted almost 2 weeks and I was really getting worried. I drank a lot of wine to have patience (thanks JasonLion), back-washed almost everyday and added bleach at a really really slow rate (don't use scented/non-splash). I was able to do this b/c of the algcide i added before starting the AA treatment. My pool finally cleared and I am still balancing cl/ph/jacks/and filter run time. I think after an AA treatment, each pool is going to be different and it sounds like a pool drain for you or paying the extra monthly expense for a good sequestrant; w/o which your stains will probably return. What i got from this site was patience in adding the cl and giving the process time to work.
I live in SoCalif so a pool drain per wife is out of the question; Jacks it is!
Good luck