Try the above advice. That's what I would do. A few back to back 50% water changes will help. With sand the longer you wash it outside the tank, the less issue like this you will have......What's your filter media? Try using just filter floss for a day or two, then toss it when it fills with the dust from the sand. Between that and settling, it should clear up within a day.
By the way, make sure HOB filter intakes are not near the bottom where they might take in sand which will destroy your impellers. When filling during a PWC let the water flow into a cup or plate and it won't stir up much sand.
Try the above advice. That's what I would do. A few back to back 50% water changes will help. With sand the longer you wash it outside the tank, the less issue like this you will have......
Yeah do the 100%, I thought the OP had fish in it!!!. In one of the pictures, do I see an airstone on the sand???Skip the 50% change and go straight for the 100% When you fill the tank use a bowl to stop from making a mess again and clouding up your water.