How to Clean an EHEIM Classic Canister Filter

Step-by-step instructions

Step 1: Record the model, hose routing and media order

Read the label and current EHEIM manual. Photograph the inlet, outlet, valves, spray bar and canister layers before disassembly. Note which media are mechanical, chemical and biological. A Classic 250 basket and a loose-media arrangement do not come apart identically, and the 1500XL has model-specific drainage features.

Step 2: Prepare tank water and contain spills

Remove aquarium water into one clean bucket for biological-media rinsing and set a second bucket near the canister for hose drainage. Place towels around the cabinet and protect electrical connections. Do not begin without room to lift the full canister upright; a tilted open canister can spill debris and disturb media order.

Step 3: Unplug and isolate the hoses

Disconnect power with dry hands. Close valves or hose taps in the exact sequence for the installed Classic accessories, then disconnect the hose block or individual hoses as directed. Maintain the siphon where the setup allows. Never rely on unplugging alone while open hoses remain below aquarium water level.

Step 4: Open the canister and remove media in layers

Carry the sealed canister to the work area and release clips evenly. Lift the pump head without stressing its cord. Remove the media from top to bottom, placing each layer in order. Keep established biological media wet in removed aquarium water. Discard exhausted carbon and badly deteriorated fine pads only according to their service schedule.

Step 5: Clean the canister body and mechanical pads

Empty sludge into the appropriate waste route and wipe the canister with an aquarium-only sponge. Rinse coarse mechanical pads enough to restore flow. Use no soap, bleach or household cleaner. A fine pad that stays collapsed or clogged after gentle rinsing should be replaced rather than scrubbed until it breaks apart.

Step 6: Preserve the biological media

EHEIM says never to clean or change all media together and never to clean it too rigorously. Swish biological rings, beads or substrate gently in removed tank water, leaving their established surfaces intact. Do not rinse them under chlorinated hot water, soak them in vinegar or let them dry. Stagger partial media renewal over separate maintenance sessions.

Step 7: Service the pump head and impeller

Remove the impeller cover and impeller by the model instructions. Brush slime and grit from the blades, shaft and well without using metal tools or bending the shaft. Inspect rubber bushings and the pump-head seal. Clean mineral deposits only with an EHEIM-compatible method and rinse every treated component before it returns to the system.

Step 8: Brush hoses, intake and spray bar

Run a long aquarium hose brush through disconnected tubing and clear spray-bar holes from the water side outward. Check for kinks, hardened tubing and loose connections. Do not enlarge holes with a drill or sharp metal pick. Replace tubing that no longer grips fittings securely or has become brittle.

Step 9: Repack media and seal the canister

Return media in the original flow order without compressing it so tightly that water bypasses or flow collapses. Clean the sealing groove and inspect the main gasket for grit, flattening or cracks. Apply only the EHEIM-approved lubricant and amount if specified. Seat the pump head evenly and close clips in a balanced sequence.

Step 10: Reconnect, prime and leak-test

Reconnect hoses and open valves in the manual's order. Prime the Classic by the approved method; never suck aquarium water by mouth or run the pump dry. Plug in and watch the canister, hose connections and pump-head seal for leaks. Purge trapped air and verify normal spray-bar flow before leaving the equipment unattended.