Abstract: A water quality measuring system includes a first introduction section for introducing rearing water as a sampling target, and a first adding section which adds an acid to the rearing water introduced by the first introduction section, and a nitrous acid sensor whose measurement target is nitrous acid and which measures the measurement target concentration of the rearing water to which the acid has been added by the first adding section. The water quality measuring system includes a second adding section which adds a base to the rearing water introduced by the first introduction section, and an ammonia sensor whose measurement target is ammonia and which measures the measurement target concentration of the rearing water to which the base has been added by the second adding section.

Abstract: An aquaculture system (Sy) includes mineral sensors (22, 24, 26) for detecting the concentrations of minerals contained in rearing water within a rearing tank (50) for rearing an aquatic organism or the rearing water within a circulation passage (70), and an adjustment section which performs instruction issuance or operation for rendering the concentrations of the minerals contained in the rearing water coincident with their standards when the mineral concentrations detected by the mineral sensors (22, 24, 26) deviate from their standards.