Turbidity, measurement of the cloudiness of a fluid, fill the tube with water and drain it slowly by limiting flow, this measurement will give you the NTU or Nephelometric Turbidity Unitinch the unit of measure for the cloudiness of the water
Transparent Turbidity Tube, simple apparatus is used to determine the transparency of water in lakes, streams, oceans as well as other bodies of water, Contains: 60cm transparent turbidity tube, rubber stopper with Secchi disc, 20cm silicon tube, Hoffman's clip, steel