The calculations above represent
minimum flows. It is good practice
to use at least twice those flow
rates (turnover times of 20
minutes) to ensure against deterioration
of water quality within
hatcheries. Additional water flow
is particularly important during
the peak of the spawning season
when the number of spawns arriving
at the hatchery and the number
of fry being reared temporarily
exceeds the planned hatchery capacity.
Thus, as a rough guide, a
hatchery expected to produce 10
million fry per season should be
supplied with roughly 100 to 150
gallons of water per minute.