I have not been able to successfully perform a CH test due to the fading endpoint. The posts I have read here say copper in the water is to blame for the fading endpoint. I do not see any signs of copper staining. Do I need to test for copper, or even worry about it? I suspect the copper came from algaecides from the previous owners. When they demo the pool to me they mentioned taking the water into Leslie's Pool and asking them to fix it.