The WATER-PAM FIBER version belongs to the first-generation WATER-PAM family. A PAM-CONTROL unit is part of the system. This unit permits stand-alone operation without power supply. The PAM-CONTROL unit also acts as interface box connecting the WATER-PAM to a Windows computer running the WinControl-3 software.

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

Two configurations of the FIBER version are available. The WATER-EDF1.5R uses red measuring and actinic light. The WATER-EDF1.5B uses blue in place of red LEDs. The WATER-EDF1.5R possesses an additional blue LED which is employed to selectively excite photosystem I in cyanobacteria for F0’ determination. In the WATER-EDF1.5B, this light source is replaced by a far-red LED for photosystem I excitation in non-cyanobacterial photosynthetic organisms.