Hey- brand new at pool-ing. Just took over a pool that sat for 2 years. When I took cover off very dark green. I started on May 4 and have shocked the pool three times, added algaecide day one as well. Since then I’ve also added stabilizer, chlorine tablets, phosphate, and although it’s lighter now...I still feel like I could use some help. Going to the pool store twice a week and feel like I’m not seeing the progress with their help. 20,000 sand filter if that helps. In eastern NC. Tips? Tricks?