I had over 100 pounds of sand for my morays and still wasnt enough. I made the same mistake with the sand except I did clean it first, just not enough. And yes took literally two weeks of syphoning and water changes until it was clear. As bad as it sounds, let it settle then sturr it back up. All the good stuff will settle in a few min and all the cloudyness you syphon out and replace with clean water. Takes a lil longer bUt your sand will look sharper after as all the cloudy dusty stuff will have been removed.