Main Line well filtration

[Doug]

I discussed the filtration set up for my sons place at his house. His main line filters would be red from the iron crud when change time came. I had some pics posted here somewhere but never looked them up yet.
Anyways, I just buying another bunch of ro and main line filters for him.

I think we tried several different micron sizes in the mains. I purchased 30m this time. I think 30m or even 50m would be the standard for mains but we discussed if something like the 10m may be better because of the iron sludge?

Whatcha think well guys.
Thanks