The weir should be pulled in toward the skimmer's drain by the flow of the water, but it is always on top of the water. Depending on how deep the water level in the skimmer is, the angle of the weir can vary. If the water is high, the weir will be a bit off perpendicular. If the water is lower, the weir flattens out. When the pump is off the weir will go up to perpendicular but bounce in and out as the water bounces in and out. It may even fall forward. The plastic side should be toward the pool and the foam side toward the skimmer.