Strange marks on driveway apron + rust stains on patio




Hey fellas. I’ve been asked to quote just the flatwork on a house. The driveway is massive and it’s a big job that I would love to do properly the first time. The first thing that caught my eye are these odd stains on the apron to their pebble driveway. I’ve got no clue what they are and I’m debating doing just the pebble and not touching the apron for the sake of it might looking worse clean vs dirty unless the contrast is too much or I can remedy the problem.

I’ve also been asked to quote their back terrace which is covered in small rust stains. I’ve successfully removed several rust stains from concrete, stone etc but none from a patio. I use new again rust n stain remover which uses hydro flouric and I’ve been satisfied with it. Just want to double check on those stains and see if anyone’s had issues on this stone. I’m doing a small test spot for sure and will set expectations accordingly.

Third thing is the efflorescence on a fountain in the back yard. I understand how tough efflo is to take care of but they’re having a party and it just needs to be gone for 2-3 weeks. Just curious if it’s even worth undertaking because of the constant flow of the water. No fish in the fountain.
Thanks gents.