water cloudy after setting in sample bottle

Have a new well 520 feet deep cased 340 feet . when a sample is first taken is perfectly clear after approximately 3 hour starts to cloud up after about 3 days settles out with a very fine yellowish layer on bottom of bottle .. seems like a very fine clay doesn't stain .. question is... is iron the only thing that settles out with air contact ?

[video=youtube;lD5dL0wp3zQ]http://www.youtube.com/watch?v=lD5dL0wp3zQ[/video]

Yes usually iron is what causes that. You might not want to allow the water to sit for hours before you use it. lol

A simple test for ferrous/total iron will tell you if it is iron, and how much is in the water and that will tell you IF you should remove it with a softener (if you have 3-4 gpg of hardness or more) or an iron filter.