No matter what kind of algae it is, bleach, bleach, bleach. You have to get your pool to shock levels, and keep it there running the filter 24/7. Brush the pool daily. Check chlorine levels 3x a day if possible, most importantly check after the sun goes down - and in early morning to see if you are losing any chlorine overnight - once you hold chlorine over night, keep it at shock for 3 more days, then let the levels fall back to normal. If you don't get it all it will start to grow back - so continue testing once the sun goes down and keep your chlorine at the high end of the best guess chart for a while. If you notice you start to use a lot more chlorine - then start to shock again.