Just bought a house in October of last year. Had to close the pool when we moved in. Didn't really know how to properly close it an don't think I did it right. When I opened it the water was dark green. I added 2 packs of shock, super algaecide, an 4 gallons of liquid chlorine. I'm still learning an afraid I'm going to screw everything up an get the CYA to high an have to drain the pool. It's a 20x40x4' inground pool with sand filter. After none of what I did helped much I hit it with 2 more packs of super shock an 4 more gallons of liquid chlorine. I also added ( forget what it's called) granules to help raise CYA a little. All other levels show good. CYA is at 20ppm. Pool is cloudy an greenish blue. So I think I need more algaecide. I put skimmer nets on the skimmer baskets an they were full of dead algae. I took them off when I added chemicals today. Might put new ones on after work tomorrow. Wish me luck. Still trying like heck to get it right...lol