We just got back from vacation. We added a starting dose of Polyquat, then shocked (however, we didn't wait the 24 hours, as we didn't realize we should have until it was too late and we were about to leave). Mid week (4 days later) my DH's parents came by & put in about a gallon of bleach. Our pool is about 5000 gallons. We put a cover (with a vented area) over the pool, but it fell in while we were away. The purpose of the cover was supposed to help keep the chlorine from dissipating as fast. Nonetheless, we came home to a clear pool.