Partial Recirculating Aquaculture Systems (PRAS) is a RAS system without the biofilter component. The PRAS system, although requiring more new water than a full RAS system calculated amount to maintain proper ammonia), still provides for a major reduction in water required compared to flow-through systems.

PRAS systems generally incorporate solids removal and gas management control (CO2 removal and O2 injection) along with UV or ozone.

See an example of a complete PRAS system we designed for Garden Creek.