Visibility Disc acc. to Secchi


Water transparency determination in lakes and oceans acc. to ISO 7027



The Secchi lens is a white lacquered brass lens with a diameter of 20cm and a weight of 1.7 kg or NEW 30 mm (made of white PVC) and a weight of 2.3 kg. It is an easy-to-use instrument for standard monitoring of water transparency in lakes and oceans. The standard sight glass (20cm) is equipped with a 3 meter long steel rope. The first 2 meters of rope above the glass have 10 markings every 20 cm for measuring purposes. The 30 cm version comes with a rope of 10m lengh and marks every 10cm on the first 8 meters.

The Visibility Disc is lowered into the water and the immersion depth is read from the marked rope at the moment the disc vanishes from sight. It is lowered another 0.5 m and then heaved slowly again. The second reading is made when the disc reappears. The arithmetic mean from both readings equals the visibility depth.



443 590Visibility Disc acc. to Secchi, dia. 20cm
with 3 m rope, marks every 20 cm
443 593Visibility Disc acc. to Secchi, dia. 30cm,
10m steel rope, marks every 10cm
on the first 8m above the disc.
443 594Visibility Disc acc. to Secchi(20cm), 10m steel rope,
marks every 10cmon the first 8m above the disc

Additional information


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