Yesterday I filled a small above ground pool (14' by 42''). The water had an immediate greenish tint. It is clear and the liner is blue. I have added shock and stuff to address ph and calcium hardness. The numbers using a strip (yes, I know those sux) are coming in line. what would cause new water to have the green tint? I am on a water system (no well). Metals? I am using the pump/filter it came with; not sw.