We recently refinished our wood floor in our old home. We rented a floor sander from Lowes and followed the DVD instructions from the Varathane company. We sanded the floors to the bare wood. We then stained with an oil based stain (olympic). When then applied a water based polyurethane from Zinsser (instructions stated it could be applied on an oil or water based stain). We sanded in between each top coat. The floor looked beautiful after the last coat of polyurethane, but then after a few days, cloudy, rough spots began to appear throughout the floor. We followed the drying time directions. What caused this and how can we repair it?