Green Water From Boiled Potatoes


I took the potatoes out to cool last evening and left water in pot overnight, graniteware. When pouring water out this morning it was a vivid green color!? Typically of course I drain the water and cool in pan  so I’m clueless if time overnight “greened” the water or exactly what happened? Please help!


The potatoes might have been exposed to light which can make the skin have a greenish hue. So this is what I am guessing caused the water to turn green.