Aquarium filter cleaning frequency depends on the media type. Mechanical media (sponges, filter floss): rinse every 2-4 weeks in a bucket of tank water you just removed during a water change - never tap water. Tap water chlorine kills the beneficial bacteria. Replace floss when it crumbles. Biological media (ceramic rings, bio-balls, K1): almost never replace. The nitrifying bacteria living on this media are what process ammonia and nitrite. Just give it a quick swish in old tank water if it looks gunky. Chemical media (carbon, GFO, Purigen): replace per manufacturer schedule - typically 2-4 weeks for carbon, 4-8 weeks for GFO, regenerable for Purigen. Filter housing: wipe the impeller and intake every 2-3 months. Clogged impellers reduce flow and cause noise. Never clean all media on the same day - stagger by 2 weeks to avoid mini-cycle.
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