Yes I need some help with my tank. I recently replaced my gravel bottom with sand and did a complete water change to my 55 gallon tank. It was cloudy at first but cleared up completley. After about two weeks my water has become a cloudy white color and a cloudy film has built up on the top of the water. I changed my two carbon filters out with new ones a day ago and no change has occurred in the clarity of the water or the film on top. I have four red belly Pacu and one 7" Common Wolf Fish. Can somone help? thanks.