Hi Nutt.
If rust was my problem,it would be easier to deal with as i would have treated the tank with Phosphoric acid before it was painted.
My problem is blasting grit. That stuffs finer than a Gnats ball hair,and it'll get where grass can't.
Hence the filter .
I get your drift though ,but i'm a fussy bastard,one of them where the light comes on in the head during the night ,get up and go to the work shop.
Dave.