I would bring my chlorine level up to shock, and keep it there, by testing 3x a day and bring the chlorine level back to shock each time. It can take a week for the cya to show up. Don't backwash while the cya is dissolving. Keep the pump running 24/7 now. You can get a floating puck basket to hold pucks while you are away - but I would raise my ph up to 7.4 - 7.6 first, because the pucks will bring your ph down. The pucks are stabilized, so they will also add cya to the pool, that's one reason everyone here likes to use bleach. It would be great if you have a neighbor to check on the pool while you are away, but if not don't worry, the pucks will add chlorine while you are gone.