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Aquatic Rack Turnover & Water Exchange Planner

Calculate recirculating rack system turnover rate, per-tank flow, and daily water exchange volume. Includes pump derate factor and commissioning checklist for aquatic facilities.

ZebrafishFacility DesignClient-Side
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Load example Rack Turnover Planner data to see the full workflow

Configuration

0% (ideal)30% (high head / old pump)

Recommended: 4-6 turnovers/hr for zebrafish

5% (low density)25% (high density / quarantine)
  • Sizing a pump for a new recirculating rack system
  • Verifying that an existing system meets turnover targets
  • Planning daily water exchange volume for a facility
  • Generating a commissioning checklist before introducing animals
  • Evaluating the impact of adding more tanks to an existing rack

Don't use for

  • For non-recirculating (flow-through) systems — turnover logic differs
  • As a substitute for professional facility engineering — complex multi-rack systems need hydraulic modeling
  • For marine or high-salinity systems without adjusting pump derate accordingly

Recirculating System Design Principles

Recirculating aquatic systems (RAS) continuously pump water from tanks through a treatment loop — typically including mechanical filtration, biological filtration (nitrification), UV sterilization, temperature control, and gas exchange — before returning it to the tanks.

Key design parameters: - Turnover rate: 4-6x/hr is standard for zebrafish; higher for sensitive species - Sump sizing: Sump should hold enough volume to prevent overflow if all tanks drain simultaneously during a power failure - Flow distribution: Even flow across all tank positions requires proper manifold sizing and balancing valves - Redundancy: Dual pumps, backup power, and float-switch alarms are recommended for any system housing live animals

Under-sizing the pump is the most common design error. Always calculate based on derated flow, not nameplate capacity.

Water Exchange for Aquatic Facilities

Daily water exchange (also called make-up water or fresh water replacement) dilutes accumulated waste products that the biofilter cannot fully remove — primarily nitrate, dissolved organics, and hormones.

Typical exchange rates: - 5-10% per day: Standard for well-established systems with low stocking density - 10-20% per day: Higher stocking density, larval rearing, or systems with marginal biofiltration - >20% per day: Quarantine, disease treatment, or systems without adequate biofiltration

Make-up water must be pre-treated to match the system's temperature, pH, and conductivity before introduction. Rapid large-volume changes can shock fish and destabilize the biofilter.

Frequently Asked Questions

Next Steps

Zebrafish Housing Systems

Recirculating rack systems with integrated filtration and UV sterilization

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Water Pumps

Submersible and external pumps for aquatic facility recirculating systems

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