This past Monday I did the usual 20% water change and now my tank has a dusty appearance. One other thing that I noticed is that my oscar's have white specks all over them and my peacocks have the same specks starting on their fins. What could cause these things? My set up is pretty simple a 29 gallon tank w/ the common spillover type filter, my oscars (2) are only about 4" and the pb (2) are only about 2.5". They all will be getting a much larger home ( Christmas will be good for them). Could this just be the filtering system, also the tank has been set up for about 5 weeks now.