Circulation
Spray bar
A small change with a large effect. It converts a single strong jet into broad gentle movement, which suits most community fish, and aiming it along the back glass produces a circular flow pattern that reaches the far end of the tank.
Short answer
A perforated tube on a filter return that spreads flow across the tank width instead of concentrating it in a single jet.
What it does
- Distributes filter return flow evenly
- Controls surface agitation by aiming above or below the water line
Strengths and where it fits
Strengths
- Reduces flow velocity without reducing turnover
- Adjustable surface agitation
- Cheap and easy to make from rigid tubing
Good fit for
- Community tanks with a canister filter
- Tanks where the return jet is too strong
Limitations and where it is the wrong choice
Limitations
- Holes clog with algae and biofilm
- Occupies visible space along the back of the tank
Poor fit for
- Tanks needing concentrated high-velocity flow