I am assuming that the plaster installed is crushed , colored quartz based product similar to DiamondBrite mixed with a white portland media.
I had mine done 3 years ago. Initiaally I was reluctant to proceed with the acid wash procedure but I am very happy that I listened.
Here it is.
Filled with 2 hoses to shorten the time and limit the hairline cracks as much as possible.
After the fill with the pump running I added 7 gallons of muratic acid to 16x32 pool with the pump running.
Now this part, to engage the pump I did against the advice.
I figured the the pump brass housing with that ppm acid solution in 22 000gal of water may be OK.
IT WAS!! Impeller is plastic anyway and I have used the pool magnet immediately after the fill anyway, so there was little chance of any cooper from that.
(I was willing to buy a new pump in order to ensure nice and even wash with the acid solution. I did not have to.)
The only thing I modified was instead of 7 days recommended I let it circulate only 5days!
It turned out to be perfect.
The only thing I could have done better, was that instead of neutralizing the acid by adding baking soda, I should have used Borax from Wallmart!!
That would raise the PH just as well and introduce the borates in the water, which is a marvelous thing to have and this way it is a lot cheaper and simpler!
I later added Boric acid anyway, since the borates are a plus in many ways to have in pool water, from the shimmering effect of the surface, to feel of water, to PH better stability and help to limit the algae start.