Notcied this a few days ago, if the water is filled all the way to the top of the tank there is a little bit of haze in the water, my tank has drained a tad and the tank seems so much clearer. I believe its because the water is not close to the lightt.
Sounds more likely that your filtration isn't up to par for the size of tank you have. Less water to filter means more cycles per hour and thus, cleaner water. I would suggest you invest in another filter.
i am running an XP3 and 2HOBs in both my 55gals.... so i would say its not lack of filtration/ turn over but surface agitation....i can kinda see what you are talking about in my tanks, if the top is stagnant..... i would just recomend more surface agitation (i pointed my PH at the surface)