Bender,
Just curious but do you know how much iron you have in your well water, and how much you have on the other side of the filter? The reason I ask is typically your well water has to be vigorously agitated for a few minutes to get the iron to precipitate which allows it to be filtered. Even after aeration it takes about 20 minutes for my water to turn brown in the open well tank pit if I leave it sit.
How about D.O. before and after?