Limestone Discoloration How to Treat

There’s threads on limestone cleaning but I need to get rid of discoloration on these columns It doesn’t look like organic stuff and front of house It looks like calcium but the owner wants to get rid of the discoloration as it looks dull Could it be calcium and what should be used??? Also there’s other areas that do have light orange on them possible irrigation stains.

Leaning towards Sodium Percarbonate

as these are not organic the owner just wants to brighten the surface

One Restore is hydrochloric Acid which I thought you weren’t supposed to use an acid

not even OA on limestone or sandstone

At least I don’t think they’re organic I’ve seen fertilizer, rust and then algae turn orange

fertilizer is a lost cause but any orangish here I doubt is fertilizer could be iron

from sprinklers even though I ran out of OA awhile ago

I’m leaning toward just using SH

Maybe the bright spots are from when I chlorinated the walls

previously and got some on the columns

if that’s the case it’s going to be no problem to even it out