When you have as many coral tanks as we do, you tend to grow an excess of coral and there’s always a small group of corals that need special care, or don’t quite have their place in the main displays yet. To deal with this, we have a special tank that is part of larger system; it is kind of like a coral annex, where new or overflow corals go to hang out until they are either given away, traded, or find their place among the rest of the coral tanks.
As a lark, about two years ago we decided to try an experiment of lighting up this small, ten gallon space with a couple of Marineland’s Accent LED lighting system which was primarily designed to be hidden in the top inside edge of the aquarium. These waterproof LEDs come in blue, red and a combination of white and blue, and they are populated primarily with a closely spaced string of low output LEDs.
Instead of trying out the white & blue Accent LED, we decided to try using just a combination of a blue strip with a red strip, and instead of purposefully mounting the accent LED, we decided to let them float right at the surface of the water. We couldn’t have imagined that was supposed to be a total experiment is now the de-facto way we run this particular halfway-house for convalescent corals.
What is particularly neat about these not-so-bright LEDs is that since they are low output they can be very close to the corals. Furthermore, the combination of their tubular enclosure coupled with the water surface creates a kind of lens that evenly distributes the light. Being placed right into the water, there is no reflection off the water surface so all the emitted light goes straight into the water space. One downside to being in the water is that over a long period of time algae does grow right on the lamps but this is enough to clean off.
Despite the tank looking purple from the combination of just blue and red LEDs, the corals selected to go in this tank really look great. Granted we’re not putting acros and SPS or chalice frags in this tank, it’s mostly Euphyllia, but there’s hardly no difference in polyp expansion and vitality. Compare the difference between the red & blue LED lit Euphyllias in these images with the Euphyllia in our Cocopeel’s coral playground – these are the same corals strains, in the same water, with about a 4:1 difference in overall PAR value.
One of the advantages of using this kind of LED light is that it is just bright enough for these moderate light corals to thrive yet it hardly grows any algae on the glass since very little light actually falls on the glass. One downside though is that the LEDs in the red strips really don’t last that long and we had to replace one after just a little over 12 months of use, which is to be expected from low output red LEDs.
We’re not advocating for coral tanks to go all red & blue LED, nor that we all start using any number of the submersible LED light tubes available. It’s simply neat to see how little some corals really need to grow and thrive even when their environment seems to be providing much less lighting energy than what is conventionally prescribed for them in the reef aquarium literature. We’ll continue to experiment with this form of non-conventional coral lighting because these corals love it, and it’s kind of neat to see what can be accomplished without the use of any white lighting at all.
