I run two Eheim 2217"s on 80 gal and once a month, I take them to the sink,open the valves and let water drain from the filter into 3 gal bucket or larger.
I then remove the pad's and rinse them out in the bucket of water,and place them on the counter or other side of sink.
I then pour the water from bucket back into filter and let it run out the hose, down the drain.
I then replace the pad's,,clean the impeller assembly,and put the lid back on after greasing the O ring with vaseline(not too much).
I then take the filter back to the tank and hook hoses back up.open valves,and plug filter back in.
have had same biological media in these two filter's for almost two year's.