To answer your questions ---

Yes, you always want the CC to be zero, although if it is 0.5 at times, that is no big deal. In regards to maintaining your other levels --- you want to make sure the pH never drops below 7.0 as any reading lower than that is acidic and will damage your pool. Since you never close the pool, just test cl and pH once in awhile and keep them in check. Everything else should be fine until swim season next year.

Glad you are still around! Merry Christmas!

Lisa