The thing is, its not all about par when it comes to growth
and coloration because par is really just measuring the intensity of light emitted. While par is important I think the spectrum is important also.
This is a quote posted by mojoreef in this thread,
Lets talk about ~Lighting~ (a very good read).
>Pocilloporin primarily absorbs green/yellow (550-600 nm) light along with some upper UV-A . it emmits a orange/red
>highly fluorescent pocilloporins primarily absorbs light from 310 to 380 nm (UV-B and UV-A) and then fluoresces this as light from 400 to 470 nm (violet/blue).
>highly fluorescent pocilloporin primarily absorbs light from 380 to 470 nm (UV-A, violet and blue) and fluoresces light from 475 to 520 nm (blue and green).
>third type of highly fluorescent pocilloporin primarily absorbs light from 430 to 490 nm (violet and blue) and fluoresces light from 490 to 540 nm (green/yellow).
>Yellow fluorescing pocilloporin primarily absorbs light from 440 to 500 nm (blue) and fluoresces light from 520 to 620 nm (green, yellow and orange).
>Red/Orange Fluorescing pocilloporin that primarily absorbs light from 500 to 540 nm (green) and fluoresces light with wavelengths that are primarily orange to red.
To understand this just read that thread, but fluoresces basically means the color you see. So if you take into consideration coloring highest par doesn't mean its the best for the corals. To get some good
fluorescence you want to be hitting the corals with 310-380 light. Take a look at this graph from Sanjay website (don't worry about the axis titles, all this basically means is the higher value the more light at that wavelength).
Whereas the xm has the highest par (great for growth), you can see how it lacks in that fluorescence range but the ushio (lower par) doesn't.
And here's a graph comparing the ushio with the blv.
Very similar but the ushio has a slightly higher par. Thats why (and with its CCT) I'm somewhat surprised its more yellow. But the blv is looking like the way to go, unless the reeflux has a similar spectrum.