Aquarium Filter Calculator
Calculate the right filter flow rate for your aquarium based on tank volume and stocking level.
The right filter flow rate depends on aquarium volume and stocking density. This calculator recommends a flow rate in liters per hour.
Pro tips
- For sensitive fish (e.g. bettas), prefer a gentler flow.
- Regular partial water changes are still needed even with a good filter.
Frequently Asked Questions
How strong should aquarium filter flow be?
As a rule of thumb, the filter should turn over the entire tank volume 3-5 times per hour, closer to the higher end for a heavier fish load.
What does stocking density mean for an aquarium?
Stocking density describes how many fish live relative to the tank volume – a higher stocking level needs more filter flow and more frequent water changes.
How often should I change aquarium water?
With normal stocking, a 10-20% water change per week is usually enough; with heavy stocking or water quality issues, do it more often.
Can too strong a filter harm an aquarium?
An overpowered filter can create too much current for sensitive fish or planted aquascapes – a filter with adjustable flow helps in that case.