What is flow rate in aquariums?
Flow rate refers to how much water a filter or pump circulates through the aquarium over a given time, usually measured in liters per hour (L/h) or gallons per hour (GPH).
Why flow rate matters
Proper flow rate helps:
- Distribute oxygen evenly
- Carry waste to filtration media
- Prevent dead spots in the tank
Too much flow can stress fish, while too little flow allows debris and algae to accumulate.
Recommended flow rates
- Community tanks: 4–6× tank volume per hour
- Planted tanks: 5–10× tank volume per hour
- High-bioload tanks: 8–12× tank volume per hour
Factors that affect flow
- Filter type and media density
- Spray bars and outlet direction
- Tank decorations and layout
Flow rate should be matched to fish species and aquarium design for optimal results.