Major pool issues and I don't know where to start. I normally maintain pool. I went out of town for 10 days with kids and left husband in charge. Pool looked great prior to leaving. CYA level was over 100 and my husband's job while we were gone was to partially drain pool to bring level down. Prior to doing this, pool became cloudy and murky. He drained about 10 inches and refilled. Then shocked using granules (gasp!) and adding pucks to chlorinator which we hadn't been using. Pool continues to be cloudy. Brown stains have appeared at creases around pool. They do not brush off. We brought water sample into pool store. Here are the readings. (we got very similar test results using our kit).
Free chlorine 0.2
total alkalinity 210
calcium hardness 250
1. How does our cya level go from over 100 to 25? We didn't drain that much water.
2. Where do I even start to get levels back to where they should be? I have no idea what to adjust first.
35 K gallon vinyl liner above ground pool.
Any help is appreciated!