The multi-parameter photometer is a mobile measuring device for liquid analysis. This allows a wide range of measurements to be made with the multi-parameter photometer. This multi-parameter photometer allows, for example, the determination of alkalinity, chlorine, cyanuric acid or also the pH value. In order to take a measurement with the multi-parameter photometer, a water sample of 10 ml must be given in a cuvette. The built-in LED in the multi-parameter photometer generates a test light on the wavelength ranges of 503 nm, 570 nm and 620 nm. A photodiode now detects the value to be measured based on the light transmission of the sample. Each measurement is automatically saved by the multi-parameter photometer. The stored measured values can then be read out via a mobile device, for example, via the Bluetooth interface installed on the multi-parameter photometer. A free app is available to analyze the measurements from the multi-parameter photometer. It is also possible to establish