When I see a cloudy tank first thing I think of is ammonia. But looking at your picture I wonder how often you are cleaning your sand bed (it looks so clean). Some of the fine sands can release dust that take a day or two to settle out, especially when the sand is new. Your power head is pointed up. Is that because it was blowing your sand bed around? How many gallons is your tank? How many gallons per hour is your canister filter? If the filter is undersized it will take longer. Obviously it could be something more complicated but I like to rule out the easy stuff first. Ammonia, and dust.
