My tank is a 90 gallon with a Fx5 and Koralia water pump #3. The stock list is one oscar 5", one firemouth 2.5", and one african knife 6". I cannot seem to get the water looking good. There are always small particles in the water and it always appears cloudy. The Fx5 is filled with pre filter in the first tray, and I just added two bags of carbon to try and clear up the water. The second is bio max and third is eheim efhisubstrat. I was thinking of adding a water pump or ac110 to try and clear it up. I do a 30%-40% water change every week. The params are always perfect. Thanks