How should filter media be replaced safely?
Written by
Kailani Okoro
Reviewed by
Prof. David Walsh, Ph.D.Replacing filter media requires a smart strategy, or your bacteria will die. Never replace everything at once. Shocking bacteria in the colonies that break down fish waste can ruin everything, leading to often deadly ammonia peaks in a few short hours if the process is not done slowly. Please don't make the same mistake I did with my first tank.
Sponges should be specially treated at the time of replacement. Cut them in half vertically. Replace only one half of each sponge every month. By doing this, you maintain your colonies and replenish this important material simultaneously. After placing the new sponge half in position, keep the old half in the filter for a new fortnight's use. It will carry over the bacterial safety.
Biological Media Rules
- Never replace ceramic rings or bio-balls unless damaged
- Rinse gently in tank water during monthly cleaning
- Preserve established bacterial colonies at all costs
- Supplement with JBL FilterStart after disturbance
Chemical Media Schedule
- Replace carbon and phosphate removers quarterly
- Swap ion-exchange resins every 2-3 months
- Always rinse new media in tank water first
- Avoid replacing chemical and biological media simultaneously
Post-Replacement Care
- Add bacterial supplements immediately after changes
- Test ammonia levels daily for 3 days
- Perform 25% water change if ammonia >0.25 ppm
- Reduce feeding for 48 hours to lower bioload
Always dose with bacterial starters, such as JBL FilterStart, whenever you change media. Does it go straight into the filter compartment? Continue daily dosing for three days and monitor their ammonia levels. This will protect your tank through its vulnerable progress period. Happy vanquishing bacteria translate into clear waters.
Cautious media handling. If you're using new chemical media, thoroughly rinse them in your tank water to remove any dust. Never use tap water. Ceramic media should be soaked in dechlorinated water for a minimum of 24 hours before being added directly to the tank. Always try to match the temperature of all water used in your aquarium to that of the aquarium itself - temperature shock is guaranteed to kill more bacteria faster than simply knocking it around.
Read the full article: Aquarium Filter Maintenance: Essential Care Guide
