PHOTOBIO Advanced Quantum PAR MeterPHOTOBIO Advanced Quantum PAR Meter The Phantom PHOTOBIO Advanced PAR (Photosynthetically Active Radiation) Meter provides accurate measurement of any light source used in horticultural applications. Allowing you to monitor the light across your grow room and adjust your light sources to ensure each plant receives the optimum amount of light. The Meter measures PAR (400 700 nm) withing a range of 0 to 3999 mmol m2 s. The ideal level for photosynthesis