I hope this is the right place for this! I wanted to make my water as crystal as possible, i had noticed it seemed a bit dusty. So i put some polyfil into my AC20 between the sponge and the carbon. It didnt seem to make a difference, so i did a 35ish% water change. (I usually only do 20, my fish got sucked up in my gravel vac and its a long story) Now it seems worse off then it was. So i just took the polyfil out. What else could be causing this? My temp is at 80. (Usually 84-5 currently calibrating my eheim) Ammonia 0 Nitrite 0 Nitrate 5 It just looks like dust being pushed around by the water flow. Is it just too small to be filtered out?