I had the worlds worst sand storm in my tank when i started. Someone on here told me to put poly fil (that crap that is in pillows you can get a bag of it cheap at Wal Mart or the Pet Store) in the back of a my hang on filter. I did this and let it run for a couple of hours then un plugged the filter, removed the poly fil, rinsed out filter and repeated. Cleared it up fast.