do not worry this is just a diatom bloom, this is normal when you cycle a tank. it will go away you might want to do a water change this will help combat this as well. Have you seeded your tank? what I mean by this is try and get a couple of cup fulls of sand from someone with a up and running tank this will help the diatom bloom as well. but this is all a normal process in the cycle.
Good luck :D