For all the proponents of what they think is “natural lighting” for corals, here’s a little bit of fodder to help them cool their jets. What is natural lighting on a reef? In shallow water it’s pretty dang close to full daylight but this realm doesn’t include the most popular corals in the reef aquarium hobby right now.
LPS corals like chalices, brains, scolymia and many more are predominantly found in slightly deeper water, beginning about 30 feet (~10m) where the lighting is attenuated to be blue, by filtering out the red end of the spectrum first. And do you know what these corals look like when you’re diving with them in their natural environment? Well it looks like they are being lit up exclusively with actinic lighting, a feature which is more pronounced the deeper you go.
In the image above you see the appearance of a Lobophyllia taken under the natural, ambient lighting which we presume is at a depth of 50 feet, give or take a few measures. In this setting the coral looks beautiful, it also looks very familiar with fluorescent red colors us reefers desire, being shown off very well by the condition of the lighting at depth.
In the image below, you can see the same exact Lobo taken with an underwater flash. The colors of this coral are almost completely washed out and look “more natural” according to how this coral is normally seen by aquarists under daylight lighting. So what is natural lighting anyway and why would we not give LPS corals the type of lighting that makes them look best, and which they experience at depth on the reef?
There’s a reason the rise of the uber colorful Acans, Lobos, Chalices and other LPS corals has been in step with the rise of LED lighting and their beautiful blue LED colors. It’s this type of blue-skewed lighting that these corals thrive under, and which makes the colors really pop in an aquarium. The point is, that if you grow LPS corals, and or you simply enjoy the look of bluer lights on your reef tank, by all means go aead and embrace the “Blue Out”.
This great composition of ambient vs. artificial lighting photos of corals at depth were made by Eunice Khoo aka MerMate.