Sump Filtration (Best)
A sump below the tank provides unlimited biological media space. Install 4 chambers: mechanical, biological (ceramic + bio-balls), chemical (activated carbon), and return pump.
Sumps keep water level stable and handle large waste loads. 20% of main tank volume as sump size is the minimum.
Large Canister (Good)
For tanks under 800L, dual Fluval FX6 or Eheim Pro 5e canisters work. Turnover should be 6-8x tank volume per hour.
Clean canisters alternately so you never lose all biology at once. Replace mechanical filter floss every 2 weeks.
Overhead Filter (Traditional)
Popular in Southeast Asia. Water pumps up to a top box with trays of media and drips back. Easy to service.
Downsides: water evaporates faster, pumps wear out sooner, and flow rate is lower than sump or canister.
Media Selection
Biological: 2kg ceramic rings per 100L. Mechanical: filter wool replaced weekly. Chemical: 300g activated carbon monthly.
Never clean all media at once. Split into halves and alternate every 4 weeks to preserve bacteria.