I would not add any Metal Magic now. I have already closed with stains, and they were gone by the time I opened in the spring I guess it's that the ph ususally goes down, and the clorine is gone too. I always add the sequestering agent before I add the chlorine in the spring. I do usually have to do a stain treatment at the beginning of the year after shocking upon opening. This year I am going to try to add a double dose of Metal Magic, and see what happens. I will keep you posted, and I hope you let me know how your pool is when you open next spring. We an all learn by sharing our experiences