Typical Minor Loss Coefficients (K)
- 90° elbow: ~0.75
- 45° elbow: ~0.40
- Tee (through/run): ~0.60
- Tee (branch): ~1.80
- Ball valve (open): ~0.05
- Check valve: ~2.00
- Union: ~0.08
Rule of thumb: a handful of tight bends can equal several feet of extra head.
Aquaponics Pump Size Calculator
Size your pump by required flow and total dynamic head (TDH). Supports US/Metric, turnover or process flow, and plumbing losses.
Results
Turnover Flow
—
Tank volume × turnovers/hr.Process Flow
—
Media/NFT/DWC requirement.Required Flow
—
Max of above + safety margin.TDH
—
Static + friction + minor + extras.Min Shutoff Head
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Recommended ≥ TDH × 1.25.Tip
Pick a pump whose curve gives ≥ Required Flow at the TDH above.
Make the Most of This Aquaponics Pump Size Calculator
Use the guidance below to choose a pump that reliably meets your required flow at the computed Total Dynamic Head (TDH).
Quick Sizing Rules
- Target flow: Use the higher of fish-tank turnover or process flow (media/NFT/DWC), then add 15–30% safety margin.
- Pick by TDH, not by “max GPH”: A pump’s advertised max flow is at zero head; match the curve at your TDH.
- Bigger pipe = less loss: If velocity > ~1.5–2.0 m/s (5–6.5 ft/s), friction skyrockets—upsize diameter or reduce fittings.
- Fittings matter: Many 90° elbows/tees can add more head than a few extra feet of pipe.
- Reserve capacity: Biofouling and filters increase resistance over time—leave headroom.
Worked Example
Inputs: 200 gal fish tank, turnover 1.5×/h → 300 GPH. Media bed: 300 L, fill fraction 0.6, fill in 10 min (sequential) → 18 L/min ≈ 285 L/h ≈ 75 GPH. Required flow is max(300, 75) = 300 GPH. Add 20% margin → 360 GPH.
Head & plumbing: 4 ft vertical, 20 ft of 1″ PVC, 4× 90°, 2× 45°, 1× tee (run), 1× tee (branch), 1× ball valve, 2× unions, extra 0.5 ft for screens. Calculator gives TDH ≈ 7.2 ft (example).
Selection: Choose a pump whose curve at 7.2 ft is ≥ 360 GPH. Verify shutoff head ≥ ~1.25×TDH (≈ 9 ft).
Head Loss Cheat Sheet
PVC Roughness (Hazen–Williams)
- New PVC: C ≈ 150
- Older/fouled: C ≈ 130–140
Lower C → higher friction. If your system clogs, your TDH increases and flow drops.
How to Read Pump Curves
- Find your calculator’s Required Flow and TDH.
- On the manufacturer chart, move to the TDH on the head axis, then read horizontally to each model’s curve.
- Pick the first model whose curve at that head gives ≥ Required Flow.
- Prefer a point near the middle of the curve (best efficiency), not the extreme tail.
If between sizes, choose the larger and add a valve to trim flow.
Maintenance & Backup
- Install unions and ball valves for easy removal and flow tuning.
- Clean intake screens and impellers on a schedule; biofilm increases TDH.
- Protect against back-siphon (check valve + anti-siphon hole where appropriate).
- Plan power backup for aeration at minimum (battery air pump/UPS).
FAQs
Do I size for turnover or media/NFT/DWC?
Calculate both and use the higher result, then add your safety margin.
Why does my real flow seem lower than the label?
Labels show zero-head flow. Real systems have vertical lift, friction, and minor losses. Always size by the pump curve at your TDH.
Will a bigger pipe really help?
Yes. Larger diameter reduces velocity and friction, often recovering hundreds of LPH/GPH at the same head.
How much headroom should I leave?
15–30% extra flow or shutoff head is typical to cover fouling, seasonal changes, and minor upgrades.
