What are your CYA levels now?

The problem with continued puck use is that they continually add CYA to your water. As these levels increase, the bleach becomes less effective at sanatizing your pool, requiring you maintain higher FC levels (see Ben's "Best Guess" chart). If your CYA gets too high (and it can get their quickly, recent info pegged the CYA content of the pucks/sticks at about half) the only way to lower it is a partial drain and refill, leading to pool downtime and possibly added expense.

Pucks are also very acidic so you need to keep a close eye on your PH levels.