Aquaponics Grow Bed Sizing Calculator

Size media beds by crop type and system flow. Get recommended bed volume, surface area, plant capacity, media weight, and hydraulic retention time (HRT) for efficient filtering and growth.

Basics
Bed Settings

Results

Recommended Bed Volume
Based on crop-type bed:tank ratio.
Bed Surface Area
Volume ÷ depth (usable top area).
Estimated Plant Capacity
From typical plants/m² for your crop type.
Media Weight (dry)
Use for stand/floor load planning.
Water in Bed (at flood)
Void fraction × bed volume.
Hydraulic Retention Time
Target ~2–5 min constant-flow; adjust by crop & biofilter needs.
If Using This Bed Footprint
Number of beds needed (optional input).
Tip
Aim for even distribution, adequate aeration, and consistent flood heights.

Optimize System Efficiency

Right-Size Beds to Your Fish and Flow

Grow bed volume should match both your fish stocking and your delivered flow. Light-demand plants (leafy greens) thrive with smaller bed:tank ratios, while fruiting crops benefit from larger beds that buffer nutrients and support deeper roots.

Depth, Media, and Oxygenation

A bed depth around 25–30 cm (10–12″) balances root support and biofiltration. Porous media like expanded clay reduces weight and improves oxygenation; heavier gravel is cheaper but increases pump work if undersized.

Flow & HRT (Hydraulic Retention Time)

Constant-flow systems often perform well when water spends a few minutes in the media. If HRT is too short, bacteria contact time drops; if it’s very long, you may be under-circulating. Tune flow or pipe size to hit your target range.

Plumbing for Lower Head Loss

  • Upsize pipe diameter to reduce friction and save energy.
  • Minimize sharp 90° turns; use 45° where possible.
  • Keep runs short and manifolds balanced for even distribution.

Iterate Safely

Increase bed volume or flow gradually and observe plant response, dissolved oxygen, and ammonia/nitrite levels. Log changes so you can correlate settings with results.

Disclaimer

These calculations are estimates intended for planning. Verify against your species, climate, and actual test readings.

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