Hang-on-back filter
Good all-around choice for beginner freshwater tanks when you want simple setup, easy access, and visible return flow.
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Filtration & Equipment
Which filter do I need?
Start with the tank size, livestock, maintenance style, and where the equipment can live. Most filters can keep a tank healthy when they are sized correctly and maintained without destroying the bacteria living inside them.
Fast answer
Match the filter to the job
Use this as a starting point, then adjust for stocking level, feeding, plants, coral, and how often the tank will be serviced.
Sponge filter
Gentle flow, strong biological filtration, low cost, and very low risk of pulling tiny animals into the intake.
Open diagramCanister filter
Useful when you want more media capacity, cleaner display lines, and flexible mechanical, biological, and chemical media.
Open diagramSump filtration
Best when the system needs extra water volume, hidden equipment, stronger oxygen exchange, and room for future gear.
Open diagramAll-in-one chambers
Good for compact saltwater setups where filtration, heater, media basket, and return pump sit behind the display.
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Decision rules
What matters more than the box
The filter style matters, but the habits around it matter more.
Do not reset the bacteria
Filter media is living biological infrastructure. Clean it gently and keep some seasoned media in place.
- Rinse reusable media in removed tank water
- Do not replace all cartridges at once
- Keep media wet during service
Match current to animals
High flow helps oxygen and debris pickup, but some fish, fry, shrimp, and long-finned species need gentler movement.
- Add intake sponges for safety
- Use spray bars or baffles if needed
- Reef tanks may need separate flow pumps
Buy what you will clean
The best filter is the one that is sized well and easy enough for the owner to maintain consistently.
- HOBs are easy to reach
- Canisters hide gear but take longer to service
- Sumps give space but need planning
Filtration is not a water change
A filter processes and traps waste. It does not erase nitrate, dissolved organics, or the need for regular maintenance.
- Test ammonia, nitrite, nitrate, and pH
- Change water on a schedule
- Do not overfeed the system
Store checklist
Bring these details when choosing
A quick photo and a few tank facts make filter recommendations much more accurate.
Size and shape
Gallons matter, but so do footprint, height, stand space, and whether the tank is drilled.
Current and planned animals
Goldfish, cichlids, shrimp, reef fish, coral, and pond fish put very different demands on filtration.
Photos and test results
Bring current ammonia, nitrite, nitrate, pH, temperature, and salinity if the tank is already running.
How you want to service it
Hidden equipment, quiet operation, low cost, easy cleaning, and future upgrades all change the right pick.