tanks were flushed at a mean hydraulic exchange rate of 26 min
(parr tanks) to 41 min (3- and 4-year-old broodstock tanks) and a
bottom center drain flow of 6–10 l/min perm2 plan area (Davidson
and Summerfelt, 2004). Flow injection manifolds were built into
the culture tank walls to allow staff to adjust water rotational
velocities by capping or uncapping nozzle inlets. Radial flow
settlers treating the water exiting the bottom-center drain (Fig. 4)
were sized at a surface loading rate of approximately 0.0031 m3/s
of flow per square meter of settling area (4.6 gpm/ft2; Davidson
and Summerfelt, 2005). The cone base of each settler (Fig. 4) was
manually flushed once daily (to the solids thickening belt filter in
the effluent treatment building) and no flow was discharged from