Is iron the problem?

[dfenley]

I just built new 11 x15 pond, with 45mm liner. Filled it, water was cloudy. Figured it was manufacturing residue. Drained it. Scrubbed off little squiggly red marks, about 1/2 inch long, all over liner. Rinsed, and refilled. Water nice and clear. Then a few hours later, milky cloudiness again. My well water is high in iron. I run it through a filter, iron reduction system for household use. Water for pond was taken directly from well, not thru household filter system.