How often should I clean my aquarium filter?
Written by
Hoang Long
Reviewed by
Prof. David Walsh, Ph.D.Regular cleaning of obviously dirty filters is the best way to maintain good quality of the water without destroying useful fish culture filtered feeding-bacteria. Different types of filter media have individual requirements: that is, it is necessary to clean some kinds very frequently; some require little cleaning but must not be disturbed more than do the fishes in your tank; while other media are fit for use only a comparatively short time.
Mechanical Media
- Clean weekly during partial water changes
- Rinse gently in removed tank water only
- Replace foam pads every 6-12 months
- Check for tears or compression damage monthly
Biological Media
- Rinse only when flow reduces significantly
- Use tank water and never scrub aggressively
- Preserve bacterial colonies at all costs
- Replace only if physically deteriorating
Chemical Media
- Replace activated carbon every 3-4 weeks
- Change ion-exchange resins every 2-3 months
- Monitor water clarity and odor changes
- Rinse new media in tank water before use
Clean all mechanical media weekly, or at the time of your 25% water change, by removing any filter sponges and gently swishing them about in your bucket of removed tank water to clear debris without killing beneficial bacteria. Regularly replacing this type of mechanical media every 6-12 months, at least, is necessary, depending on the bioload that the tank itself is sustaining, when it becomes compressed or torn.
Biological Media - extreme care now to protect your bacteria! - Your ceramic rings and bio-balls (or equivalent) are home to nitrifying bacteria. They should only be cleaned if you notice a considerable drop in water flow. Only rinse very lightly in a colander using your tank water; never use tap water, as the chlorine will instantly kill the bacteria. Replace your biological medium only when it physically breaks down.
Replace chemical media, such as activated carbon, once a month, as their effective adsorption capacity deteriorates after approximately 3 or 4 weeks. The new chemical cartridges should be washed in tank water before use, which will remove any dust they may have accumulated during storage, without requiring chlorination of the water. In the case of heavily stocked tanks, it will be necessary to change them at shorter intervals if the water gets discoloured.
Never clean all your filter media at once, as this will compromise your biological filtration capacity. Clean the filter media every other week, alternating between mechanical and biological cleaning. Staggering your media cleaning this way prevents dangerous spikes in ammonia. Always test water parameters after cleaning your filter.
Establish a maintenance routine that suits your filter type. Once again, canister filters require a full cleaning every 6 months. Hang-on-back filters require the impeller to be checked monthly. Sponge filters should be squeezed weekly. Develop a practice that suits your filter type, your own needs, and the needs of your tank.
Read the full article: Understanding Aquarium Filtration Systems
