Hanna Instruments turbidity meter for turbidity by the ISO 7027 method, one model.
HI98713-01
This Hanna Instruments turbidity meter measures turbidity by the ISO 7027 method, using infrared light.
Turbidity can be measured with white light or with infrared, and the two disagree on any sample that has colour, because colour absorbs white light and looks like turbidity. ISO 7027 specifies infrared for exactly that reason, and results measured that way are the ones a European regulator will accept.
A turbidimeter shines light through a sample and measures what is scattered sideways by suspended particles. It reports how cloudy the water is, not what is in it — and cloudiness is worth measuring precisely because it hides everything else, including organisms that disinfection is supposed to reach.
Anything that scatters or absorbs light affects the result: bubbles, colour, a scratched cuvette, a fingerprint. Sample handling matters as much as the instrument.
A scratched or fingerprinted cuvette reads as turbidity; keep a dedicated set, handle by the top, and wipe with lint-free tissue.
Supplied as one model.