The colors that are showing up look in between iron and manganese, but it's possible you have some of both. Of course, it also could be camera color error.

+ In the picture of the clumped iron, did those clumps wash or brush away easily?
+ Do you have a pole, vacuum head and hose?
+ Has the iron or whatever in the bucket test settled out? If so, how long did it take?

I'm thinking you may be able to add polyquat, settle the iron, and the vac to waste, or even to filter, if you have several extra filters, and are prepared to clean them properly.