Quote Originally Posted by hvactech2 View Post
So I should get this shock and use all 24#'s immediately?
Get it, but do not use it all at once. You don't need 50 ppm of chlorine right now!

What about maintenance shock, use the same stuff or just the chlorine pucks and/or bleach?
You can't use pucks to 'shock' a pool: they dissolve too slowly. But you can use bleach (and leave the CYA unchanged) or dichlor (and raise CYA too).