The WATER-PAM FIBER version belongs to the well-established first generation WATER-PAM family, which is controlled by the PAM-CONTROL unit. It can be operated as stand-alone instrument in the field or controlled by a Windows computer using WinControl-3 software.

The FIBER version probes surfaces of solid objects by using an optical fiber. Typically, the FIBER version is employed to examine photosynthetic layers of various submerged surfaces (periphyton, microphytobenthos) and soil crusts but also to screen samples in microwell plates.
The FIBER version is less sensitive than the WATER-PAM-II so that chlorophyll concentrations around 100 - 500 µg chl a/L are recommended for measurements.

The FIBER version can be equipped with different-colored LEDs: the WATER-EDF1.5R uses red measuring and actinic light, these light sources are replaced by blue LEDs in the WATER-EDF1.5B.

The WATER-EDF1.5R is configured with an additional blue light source to selectively excite photosystem I in cyanobacteria or, alternatively, with a far-red light source for photosystem I excitation in many other photosynthetic organisms.