mixture for seedling, and for mature;

[Richard]

Ok I've read all the letters to date [anybody else with a question should do the same, the repetition is mind numbing]
so a few questions?

When you gave your miracle gro formula you gave a mixture for seedling, and for mature; but then you gave ppm for 3 stages of veg + flowering. Is the first just a shorthand for those mixing there own without an expensive meter for PPM or shouldn't the mixture change with the 3 stages of veg + flowering?

So I know it's not Calcium Chloride it's Calcium Nitrate. I have a book Beginning Hydroponics by Richard E. Nicholls 1977, that suggests Calcium Sulphate which is what gypsum and Plaster of Paris are made of. Household item [plaster of paris] anyone know why I can't/shouldn't use it. It's very soluble does it precipitate out easily?

Just curious why is there never any discussions about NPK. Is it just understood that whatever formula you use these three are in over abundance?
Thanks
P.S. The site is much better than a lame book from 1977!