white cloudy water sounds like a bacterial bloom... something that shouldn't happen on a cycled tank. If you use a diatom filter you will be treating the symptom, not the problem. Get a test kit and measure your levels of nitrite, ammonia and nitrate (check your pH while you are at it, too). If all those are in line or if the water turns green, cut back on the feeding and reduce the lighting. Your water should look crystal clear in an established and properly maintained aquarium.
