A trusted method for measuring water quality through colour comparison.

The Forel-Ule Scale is a simple tool to approximate the color of bodies of water and is used in limnology and oceanography. Through the use of this Toolkit, it includes the Modern Forel-Ule Scale with a colour palette of 21 different colour bars ranging from indigo-blue (index 1) via green (index 10) to cola-brown (index 21) and a Secchi Disk (30 cm in diameter)with an attachment mount to connect weight and rope, you can apply a simple reliable technique to establish and classify the colour of natural waters. The color of the water body is compared to the Modern Forel-Ule scale colour palette. The result is a color indexfor the water body as we see it and thus helps to classify gross biological activity.

The color graduations correspond to open sea and lake water colors, as they appear to an observer ashore or on board a vessel. The method is used in conjunction with the Secchi disk submersed to half the Secchi depth.