# Aquaponics Water Flow Calculator

> Size the pump flow for an aquaponics system from the fish tank volume and the turnovers per hour you want, in litres per hour, US gph and gpm.

Category: Agriculture · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/aquaponics-water-flow-calculator

Aquaponic systems are sized by turnover: how many times an hour the pump moves the fish tank’s volume through the grow beds and filters.

Also called: Aquaponics pump calculator, Tank turnover calculator.

## Inputs
- Fish tank volume (default 1000)
- Volume in (options: Litres, US gallons; default l)
- Tank turnovers per hour (default 1)
- Total grow-bed volume (default 500; optional)

## Results
- Pump flow needed
- Pump flow needed
- Pump flow needed
- Pump flow needed
- Time to cycle the tank once
- Grow bed to fish tank ratio

## Formula

```
Flow = Tank volume × Turnovers per hour;  Cycle time = 60 ÷ Turnovers;  Ratio = Grow bed ÷ Tank
```

Where:
- Turnovers per hour: how many tank volumes the pump moves each hour
- Grow bed: volume of media or channels the water flows through

## Worked example
1. Flow = 1,000 L × 1 per hour = 1,000 L/h = 16.67 L/min.
2. In US gallons: 1,000 ÷ 3.785 = 264.2 gph.
3. Grow bed ratio = 500 ÷ 1,000 = 0.5.

**Result:** A 1,000 L fish tank turned over once an hour needs a pump delivering 1,000 L/h (about 264 US gph) at the working head.

## What the result means

Pump ratings fall as the lift (head) rises, so pick a pump whose curve delivers this flow at your total head, including pipe losses. Use the pump power calculator to estimate the electricity.

## Assumptions and limits
- The whole flow passes through the fish tank.
- Pipe friction, head and pump curves are not modelled.

## Questions

### How many turnovers per hour do I need?

It depends on stocking density and filtration. Heavier stocking needs more flow for oxygen and waste removal; follow your system design or supplier.

### Why does my pump deliver less than its rating?

The rating is usually at zero head. Every metre of lift and every fitting reduces the flow; check the pump curve.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/aquaponics-water-flow-calculator