So my wife picked up a bottle of Vit. C tablets (chewable, and quite tasty). After tasting one, I reluctantly dumped them in said 3 gal. bucket added hot water and then the filter element.
Next day the water was real rust colored, and the element looked... better. There's still staining on it which is likely the other sediments that might be found in ground water.

So it seems like a worthwhile endeavor. Thanks for your help!

C.