equipment
Canister filter vs hang-on-back filter
At what point is a canister filter worth the extra cost and complexity?
Short answer
Roughly above 150 L, or below that for messy or heavily stocked tanks. A canister holds several times the media, runs quietly and stays out of sight; a hang-on-back services in seconds and costs a fraction as much.
Side by side
| Dimension | Canister filter | Hang-on-back filter | Favours |
|---|---|---|---|
| Media volume | Several litres | Under a litre typically | Canister filter |
| Noise | Very quiet | Noticeable as water level drops | Canister filter |
| Service time | 20–30 minutes | 2 minutes | Hang-on-back filter |
| Cost | High | Low | Hang-on-back filter |
| Flow control | Spray bars, lily pipes, full directional control | Fixed return over a weir | Canister filter |
| Surface agitation | Only if aimed at the surface | Inherent | Hang-on-back filter |
| Failure consequence | Potential flood | Minor spill | Hang-on-back filter |
| Suits tanks above 150 L | Yes | Marginal | Canister filter |
Which to choose
Canister filter
Choose a canister above about 150 L, for messy fish, or for a display tank where hidden equipment matters.
Hang-on-back filter
Choose a hang-on-back below about 150 L, especially if you want servicing to be trivial.