This toolkit includes both the Modern Forel-Ule scale colour palette and a Secchi Disk in a sturdy packaging. The only thing you must have in addition is a non-elastic rope, and if measuring in turbulent or fast-moving water a weight of any kind.
The Forel-Ule Scale is a simple tool to approximate the color of bodies of water and is used in limnology and oceanography. This measurement requires the Secchi disk (30cm in diameter) and the FUS colour scale/palette which has 21 different colour bars ranging from indigo-blue (index 1) via green (index 10) to cola-brown (index 21). The Secchi disk has an attachment mount to connect a weight and rope. The color of the water body is compared to the Modern Forel-Ule scale colour palette while being held above the Secchi disk at half the Secchi depth. The result is a color index for the water body which can for example be used to identify gross biological activity.
