Hello, I've used all the recommendations on this site for a few years with good success, as well as the test kit that's sold. So this summer my pool has been staying virtually clear of algae and the water looks great, except for some splotchy green stains in the deep end. They look exactly like algae,they are "algae green" but won't come up or fade, and I've brushed this area until my arms gave out. I haven't used any algicides containing copper, my pool is sanitized with bottled chlorine, and I keep it at around 3 on the daily test kit. Another fact, I'm the only swimmer and so the pool gets not so much use, and I haven't shocked it in a while, it just stays clean nicely. Any thoughts? Thanks