Hi
@Wookii
Thanks for the feedback.
One of the reasons I'm drawn to the LEDAquaristik lighting is their choice of LEDs emitting at 450nm and 660nm, which correspond to the peak responses of chlorophyll b and chlorophyll a, respectively. Plus, they do show the resulting spectra for these products. Alas, they don't provide PPF* figures. By contrast, I seem to remember that most Chihiros freshwater lighting in the red emits at 630nm. I suspect that many aquarium lighting manufacturers focus (pun intended!) on lighting aesthetics whilst compromising on healthy growth. And, there's also the potential for some wavelengths to promote Cyanobacteria (aka BGA) and BBA.
*PPF = Photosynthetic Photon Flux
JPC
I'm aware you have no doubt researched this at length John, and ultimately people have to pick a light that is right for them, but my understanding is that, as long as a light provides red and blue light of some sort in sufficient quantities, the precise centre frequency of the spectral peaks is largely irrelevant.
This can be seen easily by the successful plant growth achieved across such a huge variety of light fittings, and lighting types, used in this forum alone. I don't believe any light of sufficient output will compromise plant growth in any way - output being equal, it really does just come down to the aesthetics created by the light, the user features available with it, and of course budget.
Also, if you do feel the exact spectral output is important, if you look at
@oreo57's post above on the LEDAquaristik lights, the output at 630nm appear to be only slightly less than that at 660nm in any case - presumably due to the majority of the output coming from the white LED's.
As for the algae, I've been using these RBG LED based lights for some time now, and I've only had a tiny patch of BGA once in amongst some moss where the flow was almost zero. I have had BBA, but for me it was clearly more closely linked to other factors like filter maintenance, which once rectified eliminated the BBA largely permanently. I think with both algae types, there are other factors which have a much larger influence on their prevalence than any possible effect of the spectral output of the light.