We cover essential parameters, including disinfectant levels, pH, alkalinity, calcium hardness, cyanuric acid, phosphate, dissolved solids, salinity, turbidity, and water balance. We also explains the importance of microbiological testing and outline various test methods, including test strips, colorimetric methods, comparator systems, photometers, and electrochemical methods. We conclude with best practices for water testing and hints and tips for using photometers.