Legionella is a pathogenic bacteria responsible for causing Legionnaires’ disease, a serious illness similar to pneumonia. In the natural environment, Legionella lives within in freshwater environments like lakes and streams and poses little threat. In human-made water systems, however, Legionella can rapidly grow out of control, reproducing to the point that it poses a serious health risk.

Colorimetry is a way to measure the concentration of substances that absorbs light. In a colorimetric test, a reagent is added to a water sample. If the analyte that a user is trying to detect, like chlorine, is present in that water sample, a color change will occur.  A colorimeter is an instrument used to measure the intensity of that color change and correlates that change to a useful unit of measure for the user– such as mg/l chlorine.

Only when interference filters are used is it possible to ensure that their analytical methods are reproducible. All Lovibond LED photometers use high-quality interference filters with a half-width of approx. 5 nm.

Using reference beam technology, the spectrophotometers achieve maximum accuracy in the visual and non-visual wavelength range. The light source according to the model and consists of a tungsten-halogen lamp in the XD 7000, while the XD 7500 is equipped with a xenon flash lamp.

When specific reagents are added, the water sample takes on a degree of coloration that is proportional to the concentration of the parameter being measured. The photometer measures this coloration.