It seems you didn't wash the sand enough. This step is so important as it gets rid of that sand that floats. I would suggest a 70% water change, refill it but use a plate or bowl and pour the water onto that. It keeps turbulence to a minimum. Then I would add some filter loss(polyfil) to your filter. This will catch any small or fine sand. You can then just remove it and dump it. It will also clear any clouding in hours. With sand, I would also suggest using floss continuously.
For the results it can give, check out my thread on it;