Proper selection of phosphor can also produce the same effect
Yes. But only in theory. But in practice, phosphor converted LED have a very wide spectrum, it is not usable for precision tuning of whole spectrum of fixture. Attempts to create a good spectrum by using wide spectral LEDs lead to bad efficiency. For example, white LEDs with high CRI always have a worst efficacy. To improve efficacy together with achieving high CRI is used technology of improving spectra of white LED by spectrum of red LED. This solution will give best efficacy and tunable CRI on wide range of CCT. Please familiarise with this technology:
http://ledlight.osram-os.com/technology/brilliant-mix/
Also I would like to note separately because it is extremely important. Principles of the spectrum management, contained in the description of this technology, are the basic. Without an understanding of this technology, it is impossible to talk about managing the spectrum at all. I ask also to familiarise with way, that used OSRAM to achieve good blending of different color of LED. We use the same way. To tell the truth, exists technology of better blending of colors, but it is very pricey. Diffuser, that we using, give good result and have very good price
The lower efficiency won't have a huge impact on total fixture efficiency since you still would rely on more efficeint blue LEDs to provide PAR for coral growth.
Excuse me, but low efficacy may give huge impact on expediency of LED technology at all. Please familiarise with part "Choice of LEDs"
http://www.advancedaquarist.com/2014/4/lighting
The Vero is just there to provide the white spectrum for viewing. for me the aesthetics of the light are more important than total efficiency since even a below average led efficiency is still better than a flourescent source.
As I mentioned above, attempts to construct high-CRI white LED will cause the bad efficacy in anyway. It is only cheapo, nothing more. But, to be honest, I very surprised - why many users on English-speaking forums give such high respect to Vero? There is a solution of the same class, only much better:
http://www.philipslumileds.com/products/luxeon-cob
the optics are often not needed on Vero arrays for aquarium use but they are available that are no larger or less attractive than the typical led optic.
Optics is always needed. At least to provide the passing the most of the light through the water surface, without reflection. Of course, if we design a very cheap light, we can ignore the optics. But let's see what happens if we ignore the rules of optimal design.
1. Using the low-efficiency white LEDs, but with high CRI will cause the drop of efficiency of at least 30% relative to right technology. Please study datasheets of OSRAM technology.
2. Do not use optics. Fall of about 20% efficiency. Also it depend on suspension height.
Total falling will be 0.7*0.8=0.56, i.e. almost double! It is a payment for bad understanding of simple process, that fully described in open sources.
