Hi, a couple of weeks ago I put the winter cover on the pool. It's a black vinyl cover that doesn't allow light or water through. The other day we had a few warm days and when I checked the water it was cloudy and putrid smelling (like rotting fruit). Could this be algae even though no light can penitrate? I threw in a heap of liquid chlorine and the smell is gone but still cloudy. I'm just really puzzled at what could have caused the smell and cloudiness when no light can get to the water.