Water quality measurement device and storage method for water quality measurement device

A storage method for a water quality measurement device having a flow channel through which a measurement target liquid is forced to flow, including an ion sensor which has a responsive film portion and in which a surface of the responsive film portion is disposed in the flow channel, and measuring the quality of the measurement target liquid, the water quality measurement device comprising:

• a glass-electrode-type sensor which has a glass electrode and in which a surface of the glass electrode is disposed in the flow channel;
• a drive device configured to control a flow of a fluid in the flow channel;
• a first opening-closing device which is provided at a first position and is switched between a first open state opening the flow channel and a first closed state closing the flow channel, the first position being located on an upstream side of the ion sensor and the glass-electrode-type sensor in a direction in which the measurement target liquid is forced to flow;
• a second opening-closing device which is provided at a second position and is switched between a second open state opening the flow channel and a second closed state closing the flow channel, the second position being located on a downstream side of the ion sensor and the glass-electrode-type sensor in the direction in which the measurement target liquid is forced to flow;
• and
• a supply device configured to supply a liquid to the flow channel,
• wherein, when a storage condition is satisfied, the storage method switches the first opening-closing device to the first closed state and the second opening-closing device to the second closed state, thereby producing a state in which the surface of the responsive film portion and the surface of the glass electrode are present in a common closed space, whereby the closed space is put in a wet state without the surface of the responsive film portion being immersed in the liquid.