hi, i'm trying to understand why our pool water is so prone to becoming slightly green and cloudy. the ph is at 7.2, the free chlorine at above or about 10, due to recent shock treatment non stablised chlorine; total alkalinity around 140 and stabilizer ppm about 100-150, fairly high. The filtration system is a hayward cartridge system and the pool holds about 55 cubic meters. I am beginning to suspect that the filtration rate is not adequate but the installer says it is in line with parameters. I'm beginning to think I need to put in a sand filtration system and pump. Does anyone have any suggestions to why we have continuing problems? I 'd appreciate any suggestions. Thanks