I only cleen them every three to four months. Change the pads on the pro 3 thats about it i don't mess around with the media. Don't want to kill the bacteria in it. The fx6 is full of media right to the top thats it in that one. So i don't touch it. Unless clogged, but haven't ran into that problem yet. And the eheim classics 500 gallon are not old enough to worry about yet and they only have media in them.How often do you clean your filters?