Hanna portable meter HI98703

Guide to measuring turbidity in water

Turbidity is a measure of how cloudy water is. There are many methods to measure turbidity. The best way would in a wide variety of samples is with a nephelometer – also known as a turbidity meter. turbidity meters utilise a light and photo detector to measure light scatter, and read out in unit of turbidity, such as nephelometric turbidity units (NTU) or formazin turbidity units (FTU).

Turbidity is an optical property of liquid that causes light to be scattered and absorbed, not transmitted. It is the ‘cloudiness of water’. Turbidity is caused primarily by suspended solids. It is not a measurement of suspended solids (in literature as TSS total suspended solids). Density is used to measure suspended solids. Turbidity is related to the size of particles, not density.  

EPA meters


  • Uses a tungsten lamp
  • Takes a measurement at 90° from the light source
  • Maximum cuvette distance is 10 cm
  • Focuses on NTU ratings below 40 NTUs

Bench meters:

  • HI88703
  • HI83414 (in addition also measure free & total chlorine)

Portable meters:

  • HI98703
  • HI93414 (Also measures free and total chlorine)
  • HI93102 (For pools and spas; not municipalities; log memory 25 readings). Also measures free and total chlorine, bromine, iodine, iron, and cyanuric acid

ISO meters


  • Uses an infrared LED at 860nm
  • The total bandwidth cannot be greater than 60nm
  • Recommends a 90° measurement at NTU less than 40, and a direct beam 180° measurement at values higher than this

Bench meters:

  • Choice of modes: FNU, FAU, NTC, EBC
  • Five-point calibration, ratio mode, log memory of 200 readings
  • HI88713

Portable meters:

  • Four-point calibration, ratio mode, log memory of 200 readings, fast tracker
  • Results in units of FNU only
  • HI98713
  • HI93703-XX
  • Basic turbidity, three-point calibration
  • HI 93703-11 offers data logging (199 Measurements) and PC connectivity feature 

Applications include:


  • Drinking water
  • Wastewater treatment


  • Metals and mining
  • Pharmaceuticals
  • Pulp and paper
  • Food and beverage
  • Power
  • Refining
  • Environmental 

Hanna Instruments

JHB: (011) 615 6076

CPT: (021) 946 1722

DBN (031) 701 2711






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