flagstone discoloration from pressure washing?

by dan
(virginia)

Hi-- I had a flagstone patio laid on 4" fiber reinforced slab (regular cut).

the mason used a water based sealer. half of the patio turned out perfect, the second half, the larger and more used part, he said he tried to put on the sealer heavier because of the traffic... for some reason, the stone bled onto the grout, so there were sections of grout that were bluish or greenish, coincident with the adjacent stone.

so he went back with a pressure washer around the joints of the stone to remove the seal and tried to remove the staining on the grout, then resealed the whoel patio (another coat)

I dont know if he pressure washed to much, but even after resealing, you can see all the areas he pressure washed (they are darker) and you can actually see the swirly lines from his pressure washer...

so like 1/3 of the stones now have darker perimeters that correspond to where he pressure washed, when compared to the inside, and the whole patio is resealed, and it still looks like this.

I can see the pressure washer lines in the stone, and all the edges are darker then the rest of the stone... is it possible he pressure washed too hard, and took the stone down to a diff/darker layer then the top layer of the stone that was presviously sealed and not pressure washed?

each stone looks like it has a coaster ring of a darker color on the perimeter.... and some of the stones actually have definitely obbvious daker color lines that correspond to where he pressure washed!

I can give a pic tomorrow if you need one...

what do you think happened, what can be done, and what should i have him do???

dan