Hi
I'd clean it at every water change (e.g, every two weeks).
I have a 2213 with the quick release kit, which is what i think you're referring to.
In normal operation the levers on the quick release connectors (you have 4 of them) are all in line with the pipe. The levers are taps and normally they are open.
Move all of the levers so that they are closed e.g, at right angles to the pipe. Now unscrew the quick release mechanism on the inlet and outlet hoses and your 2213 should now be disconnected from the hoses and you should not be getting wet!
Take the filter to the sink and open the levers (taps) on the outlet at the top of the unit. You have to do this, because otherwise you'll have a vacuum inside the filter and you wont be able to take the top off the filter.
Take the top off the filter, pull out the media basket and put on a plastic bag on a work surface.
Empty the Eheim cannister down the sink or toilet and clean it out with a cloth that you keep just for maintaining the fish stuff (no bleach etc).
If the filter media basket is clogged inside, you can open it up and clean up the various bits in a bucket of dechlorinated fish tank water. If you have filter wool in the filter media basket, open it up and replace the wool.
Put the basket back in the canister and fill the canister with dechlorinated fish tank water. This will help to reestablish the syphon.
Now put the top back on the filter and put all the lever taps into the closed right angle position.
Reconnect the filter and open all the taps (levers) and switch on.. your syphon should still be good.
If you get some noise from air caught in the impeller, briefly angle the external filter to help release the air.
Good luck!
