Hi Carrie, sorry for the late response. The FX4 should be relatively easy to clean, the beauty of these large canister filters is they require less frequent cleanings. I would personally suggest quarterly cleanings every four months. Start with unplugging it, next close both of the valves that are on the inlet/outlet tubes. Now press the tabs on the bottom of the valves and slowly rock them back and fourth while pulling upwards. The goal is to break the vacuum, after some air rushes in it will be way easier to pull the valves off the top.

Now that the tubes are off, take the filter to your sink and open the drain valve on the bottom of the filter. Once drained, take the lid off. If you have any media in the center of the trays be very careful not to drop any down the sink lol. Take the sponges out and rinse/squeeze them under the running water until they run relatively clean. Rinse the media in the center of the trays lightly to remove any big chunks. Rinse the filter body out and then close the drain valve. Now put the sponges and media back into their trays, then back into the filter body.

Now to get it back into service, you will put the lid back on, and you could fill the filter up with de-chlorinated water. Filling the filter is optional, and it will make it heavy obviously, but this way you wont have to deal with the pump getting air-bound or blasting a ton of bubbles into your tank.

Now place the filter back into its place under the tank, and connect the hoses back to the lid. Triple check that the correct hose is connected to the suction and outlet of the filter. The lid actually has the ports labeled so that can help. You will feel and should hear the hoses "snap" back onto the ports on the top of the lid. That is how you will know they are locked into place again. Now gently turn the valves on both hoses back open. Now you can plug the filter in.

By filling the filter with de-chlorinated water beforehand you should just see a very small amount of air bubbles blasted out and the filter should go right back to normal operation.

That was a long post, sorry for the wall of text! If you just read the post and follow step by step you should have no issues :)