I have a 20 x 40 ing ground vinyl pool with a cartridge filter. It has been 3 weeks and my pool is still cloudy. I have changed cartridges, shocked the sh*t out of it, and tried several doses of pool clarifier. The only bad reading from the pool company is a reading of 1 ppm for copper. I have added a metal chelating agent. Could this be the reason for the cloudiness?