This post was a few days ago but I have to comment so that people are well informed. This is just absolutely not true. I have had a tank running under only led blue/white for the past 4 months after switching from an led/vho setup. I have seen my corals grow and colors are coming out more and more. I have polyps that have gained new rings, brown mushrooms that now have beautiful speckles of green throughout them and a button polyp that is showing me colors I never knew it had before.
Your experience is the exact opposite of mine and many others running the same blue/white setup for over 3 months. My Zoa garden is my reference, and running only blue and cool white produces dull reds, oranges, blues, greens, and purples compared to running a fixture which adds red, violet, cool blue, warmer whites, and some green/cyan. Acans and SPS are the first to lose their color under blue/white, especially red ones, or shallow water SPS that possibly utilize 660nm and 420nm for photosynthesis, which cool white/blue do not provide.
I can reproduce it visually as well. Once I turn off my color channel of LEDs, and only run blue and white, you can see the difference. That's even with neutral and warm whites, which have a wider spectrum available than cool whites. The same faded Acans and zoas under strictly cool white/blue also colored up within weeks and retained it once I switched.
The absolutely not true part is subjective and not accurate unless you've tested both setups like I have, and with a wider range of coral. I haven't even been able to test many SPS, but they also can lose color. This is readily seen with people selling their ai Sol blue units on sps tanks and going back to halides.
You would have to see older pics posted, as because of the hurricane, I may be out of power for a week or more, and will most likely lose my tank.
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