Zozo not to be contradictory I’m just raising some questions.
I think we are all on the same page i.e.we are having a discussion aka peer review, no body is saying these are the facts and we are all open minded on the subject
The statement that no other lamp could provide what the sun provides in terms of light intensity is I’m afraid not in line with reality.
Think @Andrew T has made a very valid point here esp we consider Reflection and Refraction with our tanks with fixed lights the incident angle is constant so the light intensity will be constant if the lights output remains constant. However with natural light the incident angle of the light will be constantly changing as well as the light intensity, also the incident angle will change on a daily basis as the sun climbs/falls in the sky. So maybe our fixed lights above our tanks do bombard our plants with more photons than a tank receiving natural daylight light in a single photoperiod, not says always do, but maybe more than with think