I wanted to let you know that the height of the fixture has a HUGE effect on par levels at the surface of the corals. Light intensity absolutely attenuates in the air, to much greater extent than you think.I am respectfully confused why we are debating the height of the light fixture above the water. The light does not attenuate in the air, so height little direct effect on the intensity in the water. However, the height will cause the light to diffuse over a larger area (lowering intensity) when raised high and focus on a smaller area (intensify) when lowered. All of this is interesting to debate until you go back to the data provided: Biznizface has measured the light with a Seneye. Provided this measurement was done correctly, we can debate the ideal PAR numbers, but arguing fixture height and %power is missing the point. PAR is PAR. It's either appropriate or not. A PAR value of 300 that is mostly uniform at the depth of the corals seems almost ideal for SPS, right??
It is the inverse square law. Which basically means that given a distance of x, the intensity is reduced by the square of x.
so. if you had a light at 6" and you went to 12" above the water, you will now have 1/4 of the light intensity at the source.
this may help understand..




