When I closed the pool last winter I did not leave enough water in the pool. As a result, the water table pushed the liner up and when it settled there were a million creases. So I bought a new liner, filled the pool up with water and now we had 5 inches of rain and I'm noticing a couple creases in the liner again. Is there a way to get the creases out? What do I need to do to prevent more creases?