I inherited a very old pool when we bought our home. It came without a weir. Found this universal one with spring loaded hinge. I thought the flap would go down when the pump is off to trap the debris (thought this was the purpose of the weir). It does not go down. There is some styrofoam on the weir and I have that facing inward toward the skimmer. Am I supposed to remove the foam. Is the weir supposed to close? Do I have my water level too high? What am I missing here? Thanks!