We recently rented a sander and sanded our Dining Room floor. We were told to immediately seal it with a poly to prevent the floor from retaining moisture. Before we sealed it with one coat, one of our children spilt water on it. It was wipped up immediately but not before the wood accepted it. We carefully sanded it and sealed it with one coat of poly hoping the marks would disappear but not the poly does not seem to be covering the wood. Any suggestions would be helpful befor the floor is buffed and the other coats are put on. Thank-you.