Think of "shock" as a verb, an action, not "stuff". That way you'll always know what you are doing.
I shock almost exclusively with Liquid Chlorine (Same as bleach only twice as concentrate). I currently don't have ANY Cal-Hypo or Di-chlor in the house, and only a tiny bit of 1" Tri-chlor tabs.

I went into my favorite pool store yesterday (the one where they actually do NOT sell calcium boosters to vinyl pool owners) and asked for CYA. Kid didn't know what I wanted. "Cyanuric Acid. You know, Stabilizer". "What do you need it for?" he asked. I said "Are you kidding me? I know EXACTLY what I need it for." Then he went into a song'n'dance about how people use too much (true) and how I shouldn't buy more than one lb. I said "Look, I know how to use this stuff and even how to run a high chlorine pool." Pretty funny.

Carl