How to Maintain a Fluval Filter

Unplug the Fluval filter pump's electrical cord from the outlet. Close the "In" and "Out" valves of the filter pump by turning them to the vertical position. Remove the lock nut by turning it clockwise with your fingers. Pull out the rubber drain cap located under the lock nut. Check the purge valve. If it is not in the closed or vertical position, turn it to that position now.

Insert the purge valve opening into the end of a flexible 5/8-inch hose. Clamp the hose onto the purge valve opening with a 5/8-inch hose clamp. Tighten the screw on the clamp to secure the hose onto the purge valve. Place the other end into a bucket.

Open the purge valve by turning it counterclockwise into the horizontal position. Press the release button of the "In" valve and remove it from the filter lid. Use a towel to catch any water that spills out when you remove the valve. The water in the pump will drain once you press the release valve. When it stops draining, close the valve, empty the bucket and open the valve once more. Keep removing water until the filter canister is light enough for you to carry safely.

Close the valve and remove the drain hose. Replace the drain cap and lock nut. Turn the lock nut counterclockwise until it is hand-tight. Remove the "Out" valve from the pump. Unscrew and remove the eight lid nut fasteners. Remove the filter lid and set it in a safe place. Take care not to damage the inlet stem that is connected to the lid as you do so.

Pick up the three stacked circular media baskets by their orange T-handles and remove them from the filter canister. Remove the T-handles from their slots and separate the three baskets. Remove the foam inserts from the baskets and rinse them with pretreated aquarium water. If the chemical media in the basket is dirty, replace it now. Rinse off the biological media of the baskets with pretreated aquarium water or replace it.

Empty the filter canister and rinse it off thoroughly with pretreated water until clean water runs out of it. Replace the filter canister. Reinsert the foam inserts and filter media. The foam inserts need to cover the entire half circle of the basket from top to bottom while leaving 1/2 inch of free space above the top of the filter media so that the baskets will stack into the canister. Stack the baskets and realign them. Insert the ends of the T-handles into the vertical slots on the sides of the baskets. Insert the baskets into the filter canister. The foam at the top of the top basket should align with the top edge of the canister.

Replace the lid gasket, if it is worn, by prying it out with your fingers and inserting the new gasket into its seat. Reinstall the filter lid on the canister. Press the lid down until the output tube sits in the output valve lid opening. Reinstall the eight lid fasteners and hand-tighten them. Put the "In" and "Out" valves back in place. Connect the "In" valve to the hose of the intake strainer and the "Out" valve to the hose attached to the output nozzle. Turn on the "In" valve and the "Out" valve. You should be able to hear the water as it refills the canister. The "Out" valve hose will release the trapped air of the canister into the water and cause it to bubble. Observe the bubbling and, when air stops churning the water, plug the electrical cord back into the outlet to turn the filter back on.