Finally, A Better PAR Sensor - Apogee's ePAR

[Pny]

I can not see how this device would give any new insights of radion below 400 nm??? According to the manufacturer specification the Apogee MQ-650 has a range of 400-750 nm (?) while the MQ-510 goes slightly lower (389 to 692 nm) and the MQ-210X even lower (370 to 650 nm). BUT... according to the graph the MQ-650 and MQ-510 would go equally low.

https://www.apogeeinstruments.com/content/MQ-510-spec-sheet.pdf