Thanks for the replies. Carl, you are correct that my chlorinator uses the pucks. Not a SWG.

Just so I've got this straight, once I drain the pool I should stop using the pucks permanently and switch to bleach. Correct?

You also said if I decide not to drain and refill. What are the pros/cons (I'm guessing mostly cons) in that method?

Thanks very much for the help, I really appreciate it!