I just tested the PH on the drained water. It was between 7.3 and 7.4.You should leave it there for no more than 24 hours. The reason why you leave it there is to moistened the bottom of the container for that is where dry spots occur most. Just either pour it out within the next 24 hours or use a turkey baster. Before I do toss it away I test the runoff pH though.