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Aquaculture Tank Calculator.
Aquaculture Tank Calculator
Recirculating Aquaculture System (RAS) sizing — fish-only, no plants. Tank dimensions, biofilter, mechanical filter, pumps, oxygen, full BOM.
RAS components in order
| Component | Purpose | Sizing rule |
|---|---|---|
| Fish tank | Production volume | 0.5-1 lb fish per gallon water (max 2 lb/gal in well-aerated systems) |
| Mechanical filter (drum / radial flow) | Remove solids before biofilter | ~10% of system flow rate; clears 50+ micron particles |
| Biofilter (moving bed / fluidized / trickle) | Convert ammonia → nitrite → nitrate | ~10-15% of fish tank volume; 200-300 m² surface area per kg feed/day |
| Degassing column | Strip CO₂ buildup | ~2-5% system volume |
| Oxygen / aeration | Maintain dissolved O₂ > 5 mg/L | ~250-350 g O₂ per kg feed |
| Heater / chiller | Maintain species temp | Sized to room ΔT × heat-loss rate |
| UV / ozone (optional) | Pathogen control | ~30-50 mJ/cm² UV dose |
| Sump tank | Reservoir + redundancy | ~10-20% of fish tank volume |
| Pumps | Flow circulation | System turnover every 30-60 minutes |
Common RAS failure modes
| Failure | Cause | Prevention |
|---|---|---|
| Power loss → fish kill | Single-point dependency on grid | Battery backup + alarm + automatic generator + high-DO buffer |
| Ammonia spike | Biofilter fails or wasn't cycled fully | 30-day cycling before stocking; gradual stocking; daily ammonia testing |
| Disease outbreak | Stress + density + introduced pathogens | Quarantine new fish; UV/ozone; biosecurity; reduce stress |
| Oxygen crash | Aerator fails or system overstocked | Backup aeration; redundant blowers; DO alarms |
| Temperature swing | Heater/chiller fails | Backup heating; high thermal mass; alarms |
| Plumbing failure → flood | Pipe break, drain block | Floor drains; standpipes + emergency overflow; insurance |
Aquaculture vs aquaponics
| RAS aquaculture | Aquaponics | |
|---|---|---|
| Output | Fish only | Fish + vegetables |
| Nitrate handling | Discharge (treatment) + water exchange | Plants consume nitrate |
| Water use | Daily 5-10% exchange typical | Top-off only (~1-2% daily) |
| System complexity | Lower (simpler nitrogen mgmt) | Higher (must balance plants, fish, biofilter) |
| Capital cost | Higher per fish lb | Lower per total revenue (two products) |
| Best for | Commercial fish production at scale | Diversified small-medium farms |
Free under CC BY 4.0. Cite as "OAT Aquaculture Tank Calculator (openagriculturetechnology.com)". Sizing methodology from Timmons & Ebeling "Recirculating Aquaculture" + university extension RAS publications.