Secchi disk

(6 customer reviews)


*NEW reel! Measure more precisely*

The Secchi disk is a simple device used to measure turbidity, which is essentially the water clarity.

Though high turbidity is often a sign of poor water quality and land management, crystal clear water does not always guarantee healthy water.  Extremely clear water can signify very acidic conditions or high levels of salinity.

Bulk discounts available. 10% off 5 or more.  15% off 10 or more (discounts applied once in your shopping cart).

Sold By: Water Rangers Store
SKU: WR0024 Category:



20 cm diameter
Opposing black and white quarters
Calibrated line attached, measuring tape reel


Turbidity is a measure of the ability of light to pass through water, essentially the measurement of the water’s murkiness. Measuring murkiness gives an estimate of suspended solids in the water. Turbidity measurements also take into account algae and plankton present in the water. Secchi discs’ ropes are marked at half metre and metre intervals. You measure how far you can lower the disc into the water until you can’t see it anymore. This is known as the secchi depth. If your disc touches the ground, but you can still see it, you can record ‘bottom visible’.




Additional information

Weight .67 kg
Dimensions 21.5 × 20 × 5.5 cm

6 reviews for Secchi disk

  1. Kim Emde

    Simple and easy to use, the Secchi disk provides extremely valuable information to add to your testing regimen.

  2. Jenn Cuff

    The secchi disk is easy to use. The design could be improved with a “firmer” material to wrap the line around… perhaps a thicker square shape foam, or a “tubular” shaped material. Recording water depths could be more precise with improved markings (painted depth markings on the rope)

  3. Greg Ellis

    A nice lightweight (but not too light) Secchi disc that is also useful for checking water depths. Easy to store and easy to use!

  4. Kathryn Lindsay

    The secchi disk provides a couple of valuable measurements: water clarity and for locations that are not too deep, water depth. It is easy to use, durable and stores well in the Water Ranger kit. 1 m lengths are denoted by flagging tape; 0.5 m by a knot in the line. It would benefit from more measurement markers on the rope perhaps every .25m for knots (with flagging still a 1 m intervals). I found the spool for the line worked fine, was lightweight and presumably floats (didn’t have occasion to test) as long as the bottom is closer than the full length of the line!

  5. Jérôme Marty

    Start using the simple and yet effective most popular disk for freshwater scientists: the Secchi Disk ! This year marks the 200th anniversary of Angelo’s Secchi’s birth and therefore a long history of measurement of water clarity.
    This tool is recommended for everyone starting to measure water quality. Everyone (not just scientists!) can use it: just lower the disk in the water and see it disappear to assess the Secchi depth. The Secchi disk comes with a rope and weight to make sure it goes down easily.

  6. S. Dubreuil

    Fantastic piece of kit. Used to establish both water clarity and depth in shallower waters. Is very simple to use and gives immediate, tangible information about visibility. Great info for scuba divers as well.

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