It just looks a tiny bit hazy to me. Did you just get a new filter? Because when I got a new filter my water was a little hazy. How long ago did you set up the tank?
This tank has been running for about 4 months, it gets water changes about once a week. About 40-50% water change. Light refracting off the water? Could you be more detailed. It just had a water change about two days ago.