Why do my cichlids keep rubbing there sides on the rocks...?

I have a 75 gallon tank and we recently moved, about 2-3 weeks after the move our water didnt look right, turns out we had very high nitrite levels so we started doing daily water changes and adding double quantity of cycle into the tank. The fish started flicking their sides on the rocks and tank ornaments. We thought it was ick so we treated the tank for that, there are no white spots on any of them now however they continue to flick themselves and the water looks almost cloudy or like water looks sometimes when you first pour it into a gl from the tap and there are the white particles in the water. I am lost as to how and get there water under control as I have never had this problem before. How do I lower their nitrite levels? And could them flicking themselves be stress related or does it have to be ick still? I am thinking of changing 75% of the water and essentially starting over with the water but I dont know how the nitrites got so high in the first place.