Fluid monitoring system and method

A fluid monitoring system for determining a property of a test fluid, the fluid monitoring system comprising:

• a main fluid flow path through which a test fluid can flow;
• a primary sensor set comprising at least one primary sensor configured to provide a primary-measurement signal indicative of a first property of a test fluid flowing through the main fluid flow path;
• a secondary sensor set for use in calibrating the primary sensor set, the secondary sensor set comprising a secondary sensor configured to provide a secondary measurement signal indicative of the first property of the test fluid, wherein the system is configured such that the secondary sensor set can selectively interact with test fluid;
• and
• a control unit configured to:
• acquire a first measurement based on the primary measurement signal of the at least one primary sensor and acquire a second measurement based on the secondary measurement signal of the secondary sensor;
• compare the first measurement and the second measurement in a calibration operation to determine an adjustment for calibrating the primary sensor set based on the secondary sensor set;
• and
• determine a first property of the test fluid based on (i) a primary measurement signal of at least one primary sensor of the primary sensor set from the first measurement and/or a further measurement and (ii) the adjustment.