Our Process

RAS Water Flow

Our Recirculating Aquaculture System uses a continuous loop of mechanical, biological, and UV filtration to maintain optimal water quality for purple sea urchin ranching at our Fort Bragg facility.

Clean Water Supply
Dirty / Waste Water
Treated / Filtered Water
UV-Sterilized Water
Biofiltered Water
Water Flow Sequence① Holding Tanks → ② Sump Dirty Side → ③ Fluidized Bed Biofilter → ④ Sump Clean Side → ⑤ Rack Pump → ⑥ UV Sterilizer → ⑦ Back to TanksContinuous recirculating loop · Mechanical + biological + UV filtration · Gamete containment via filtration & UV sterilizationURCHIN HOLDING TANKSBasket culture · 5–10 GPM per tankBasket 1Basket 2Basket 3Basket 4Basket 5Purple Sea Urchins (Strongylocentrotus purpuratus)1Waste return2DIRTY SIDECLEAN SIDESUMP TANKFILTER PAD TRAYDacron 150ftWaste waterSilica MediaAFMSHIGH · 6 × 50 lbTreated waterFLUIDIZED BEDBIOFILTERFBB15-012 · 15″ · 12 GPMNH₃ → NO₂⁻NO₂⁻ → NO₃⁻NitrificationAmmonia → Nitrate3Biofiltered → Clean4From clean sideRACK PUMPMPD2400 · Danner 2400 GPH5MUQ040-080 Quartz SleeveUV STERILIZEREmperor Aquatics SMART 80WMUVP080 · MUL080 LampGamete destruction · BiosecurityService Kit: MUVORGK-OR (×2)6Sterilized water → directly to holding tanks7

System Parameters & Water Quality Targets

Temperature10–17°C
Dissolved Oxygen80–100% sat.
pH7.8–8.4
Salinity32–34 ppt
Ammonia (NH₃)<1 ppm
Nitrite (NO₂⁻)<1 ppm
Nitrate (NO₃⁻)<100 ppm
BiofilterFBB15-012 · 12 GPM (45 LPM)
Pump Capacity2,400 GPH
UV System80W · Gamete sterilization
Sump26″ × 57″ dual-sided
Filter MediaDacron + Silica (coarse)

Water flows from holding tanks to the sump dirty side, through the fluidized bed biofilter, back to the sump clean side, then the rack pump pushes it through the UV sterilizer and directly back to the holding tanks. The UV sterilizer serves dual purposes: biosecurity against pathogens and destruction of urchin gametes to prevent environmental escape.

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