running w/fish crystal clear? I started my 20 Gal freshwater aquarium with sand and let settle 24hrs before turning on my filter to let the bio stages set up for a week, water was good after the week so i added my 4 guppies, dwarf frog, mystery snail and rubber lip pleco slowly over a few days and everything was crystal clear for a week. I recently added 2 long finned tetras and 2 Buenos Aries and now it is cloudy...=(