If you have well water what probably happened was the chlorine caused the pH to increase just enough to cause the water to change color (high pH = flourescent/lime green) – and then additional shock pushed any dissolved metals out of solution (iron = dull green/brown).
What I would do would be to add pH- to bring the alkalinity and pH down, followed by FerriTabs to take the metal out of the water. *FerriTabs work best with Sand filters, though there is also a special formulation for cartridge or de filters.