Hello TFP. I love your site and get great information from reading old posts, threads and consider TFP extremely helpful as a new pool owner. My problem is that I'm consistently opening my in ground pool to algae, cloudy green water color and 0 FC even though I close it with sparkly clear PH balanced water with a FC > 6.0 and CC < 0.5. I have a safety cover in excellent condition that's used during the winter months while closed for the past two years. I switched from a cheaper cover that used the water bags to hold it down. This is the only change I've made over the last 5 years regarding the pool opening/closing process. The openings take about a week of slamming and +$150 of shock or chlorine to get the water clear.
My question - Is this normal of other northern in ground pool owners opening to this algae, cloudy green water quality? I've been an in ground pool owner for about 5 years but memories from the 1970's of my parents above ground pool (Hendon 40x16x8 rectangle) opening were much better water quality. I feel like the water is getting contaminated somehow over the winter and every worm in the area crawls into the pool which I vacuum out during slamming. I've also measured ammonia in the water 2 years ago and slamming took much longer. One other suspicion I have is that the concrete isnít pitched correctly around some areas of the pool and any water that enters the expansion cracks will drain into the pool. So, fall and spring rains plus melting snow water will partially get drained into the pool. Please let me know if you need more data about my question and thanks for any help.