My yard flooded into the pool. I have never used the manual vacuum before only my Dolphin, which I do t think would be good to put into this mess. . If I vacuum to waste do I move the lever by the pump to close the main drain? Does that put all the suction at the skimmer for the vacuum to work? Or do I leave that lever where it is in the middle between main drain and skimmer? Thank you for any help!