What, blue versus white, lighting combo gives the best coral growth?

AlexandraDreadlocksPanda · Jun 12, 2023

ReefGeezer said:
Not as simple as Blue vs. White. White light is made up of all the color spectrums that include the blue spectrum. Generally speaking, the most beneficial light for corals and their zooxanthella is light in the violet to blue green portion of the spectrum (that includes blue) and a little in the red orange to red spectrum. These colors are at each end of the visible light spectrum. Corals really don't use much of the yellow and green in the middle of the spectrum. Unfortunately, there is normally a lot of those in standard white lighting. It may be that the benefit of using white light is just to replace the red spectrum that is missing from blue lights.

To clarify a little, those parts is the spectrum *can* be utilised by zooxanthellae, but it doesn’t mean they are both necessary…. Photosynthesis can carry along quite happily just under one section, so it make sense to exploit the biggest section of wavelength that is useful, the uv & blue section. Red, yellow and green light will help nuisance algae’s….

AlexandraDreadlocksPanda · Jun 12, 2023

I think far more important (within reason) than the actual spectral output is uniform distribution of correct par, and correctly acclimatising corals to the new conditions. Also having flow and nutrients appropriate to light levels…

I run virtually all blue/ uv, on my RSR525xl I have:
5 x Orphek OR3 150 RB+
2 x Orphek OR3 60 RB+
2 x Orphek OR3 60 UV
1 x Fluval Sea Marine 3 (just for a touch of white so fish don’t look washed out!)

Frag tank is 2 x RB+ 1xUV Chinese bars.

Timfish · Jun 12, 2023

Like everything else in reef systems, what matters are the specific requirements of a species in question. There is no "ideal" spectrum/intensity combination.

Contrasting Light Spectra Constrain the Macro and Microstructures of Scleractinian Corals

The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions ...

www.ncbi.nlm.nih.gov