Hire a high presure sprayer.
YOU DONT
Yes just be careful that the hydrostatic valve works in case of ground water causing the pool to start floating.
That could depend on your on which part of the country in which you live and the make up of the water. Meaning, is it alkaline or acidic? The best possible short answer may be to use the best quality...
Just put hydrochloric acid in your water
I believe if you check with pebble tech they will say never.
Learn how to Open a Pool - Removing the Pool Cover
Learn how to Open a Pool - Brushing, Skimming, and Vacuuming
Learn how to Open a Pool - Miscellaneous Items
Learn how to Open a Pool - Proper Chemical Balancing