I know how frustrating it is A couple of seasons ago, I kept the stain dance going. Last year I hardly had any stains. This year I had a lot of stains at the beginning, but now I haven't had any bad ones since putting in some ascorbic acid. I do find that using pucks or calhypo seem to add to stains. I have my cya at around 60 now. I am still not sure why sometimes the sequestering agent works, and sometimes the stains keep coming back no matter how much is in there. Every time I see some stain start, I take my ph back down, add some sequestering agent and they go away. I try to keep my chlorine at the level of the best guess chart. It is a balancing act, and sometimes the stains don't come off with the sequestering agent. I then just add some ascorbic acid around the perimeter of the pool and they disappear without taking the water out of balance (just lowers the ph a bit). I do keep my filter running 24/7, I think it may help with staining, but not much. I wish I could be of more help, but it is just not an exact science. I will keep trying to find out what works, and if everyone with stains posts what works for them we can learn from each other.