When I got home today water was running out of the top of the skimmer after some heavy rains today. I backflushed for several minutes to get the water out of the pool. When I turned the pump off after backflushing and rinsing I noticed the water was still flowing out of the waste line and it appeared to be coming from the pool - I could see it moving in the skimmer. I've never paid much attention when backflushing before this. Is this normal? The water did not stop flowing until I moved the handle on the filter valve back to the normal filter setting.