I can't comment on the mps, I'm sure Ben or Chem-geek will be along shortly to address that...

BBB shock is simply the addition of chlorine, (most of us use bleach), to an elevated level to kill off all the nasties, including the CC, in the pool. Bleach is $2.54 for the large size generic jug at our WalMart, and how high you need to take your chlorine depends on your CYA level (if you can see the blue links in my sig, check out the "best guess chlorine chart" for info on chlorine levels based on CYA). I use about 4 of the large jugs a week in my 29K gallon pool, so for just over $10 weekly I can keep my pool crystal clear. If you stay on top of your testing and chlorine, there's rarely a need to shock the pool. You do need to be concerned about your copper heater no matter what form of chlorine you're using--but it's not the chlorine that's the problem, it's the pH below 7.0 that will dissolve the copper into your pool water and create problems. Bleach doesn't change your pH.