I assume you're using Brewtan B to chelate those metals?
That makes sense. I'm lucky that my well water is fairly soft, and once I chelate the iron and manganese it makes a nice starting point for most beers.
That said, I can't brew with my well water since it has back manganese in it which kills the yeast and makes thee beer taste like crap. I only use RO water (yes I have one of those as well) and build my water profiles from there.Have you tried Brewtan B? I have quite a bit of manganese and iron in my well water, and when I started treating with gallotannin my flavor issues went away.
I could use that, but my water sucks over 400 grains of hardness. It is easier to just use RO and build my water profile with Bru'n Water.
It's pretty trippy waking up on brew day to see my brewing water purplish blue. It's not unlike as if someone added a few drops of iron gall ink to the water. But it all seems to fall out with the trub, and the flavor difference is remarkable.
I actually use a product for winemakers called "FT Blanc Soft" by Scott Labs. When the info on BTB was first making the rounds, but the product wasn't readily available at the homebrewer level, I started looking at gallotannin products marketed to winemakers. This product is specifically to reduce oxidation in white wines, so I rolled the dice and gave it a try with great results. I assume that BTB will work just as well, if not better. But at my usage rates, I have a few years supply of the FT Blanc on hand and no great impetus to change.