As far as I know, the rate ofchlorine feeding into the pool depends on where you have the flow rate set, not how many pucks are in the feeder, so I really think how many pucks to add depends on how often you want to refill it.

You're not going to be able to shock the pool using pucks, i t will never feed enough chlrine at one time, so you need to use another chlorine source for that.

Janet