manny09 - I typically use the garden hose to remove all the junk from the filters (don't was the bio-balls or media that houses the bacteria) once a week when I do a water change. I like to keep my tanks clean. After hosing them off I stick them in a buck with decholiranted water for about 10 mins then stick it back in the sump. I change the filters out when they look ragged and old, usually anywhere from 3 to 6 months.
Not sure what a skilter 400 is.
"Talk does not cook rice" - old Chinese proverb
(I think it means stop talking and start doing)