Re: Can scaling develop within one week of bad water chemistry in a new pool?
There are several possibilities for the discolorations, and there may more than one problem going on. And Pebble Tec should send a rep to inspect your pool. Did you provide them some pictures?
If the dark areas (which are in trails or streaks down the pool floor) are the original and intended color, it may have been caused by an acid wash immediately after the plaster finish was installed. It may be that the crew allowed a strong acid solution to run down those areas, thereby etching the surface where it is dark.
The white trowel marks may be from the plasterers (troweling finishers) that added and used excessive water while troweling and causing excessive porosity. White spotting can also be of the same cause.
Also, in time, porous areas or spots caused by the finishers or start-up crew can slowly turn white and appear to be scale, but it is not. A porous surface becomes much lighter in color than the surrounding smooth and dense plaster surface.
Out of balanced pool water (high pH) would cause uniform whitening on a uniform quality plaster surface, not in streaks, spots, or mottled blotchiness.
Without personally seeing your pool, I can't say if it has white scaling deposits or not. But again, since there are dark areas that are rough, and whitish areas that are smooth, it is likely that something else (other than the water balance) has occurred to cause those conditions. A pH of 8.2 does not necessarily cause scaling conditions, especially since the other water parameters were in balance. If the pH was actually higher than 8.4, then uniform white scaling could develop, but which would also be rough to the touch and easily removed.
You also mentioned that the Pebble Sheen color is a "blue" granite. If a color pigment was added to obtain a bluish color, and the plasterer also added calcium chloride to the mix, that is a non-compatible mix, and will likely cause mottling and blotchy whiteness. If an "organic" blue pigment was used, the color can easily be bleached out by normal chlorine residuals. Organic blue pigments should not be used in swimming pool constructions.