Nowadays, almost all refugia have macroalgae and other types of plants in them. This means that they require a light source of their own. Luckily, there are now aquarium lighting systems that are specially designed to provide the very high intensity needed for this as well as a plant-specific spectrum. Moreover, the very best of these specialized fixtures (for example, the ChaetoMax Refugium Light
) are made to fit nicely into the often clamped overhead of a refugium space.
Being as your planted refugium will probably be the single most important component of your aquarium’s life support system, and lighting quality will affect its performance more than anything else, we should elaborate on this a bit.
No refugium macro can do its job, much survive, unless it receives sufficient photons to carry out photosynthesis. The compensation intensity is the minimal amount of light a plant must receive for its gross rate of photosynthesis to equal its gross rate of respiration. In other words, it needs just enough light energy to make just enough sugar to at least maintain its basal metabolism. Growth occurs only after the compensation intensity is exceeded. The uppermost growth limit is reached at the saturation point; this is the intensity at which its photosynthetic machinery is working at maximum capacity.
Let’s just put it plainly here: Natural sunlight is incredibly bright. You’re never going to reach anything near the saturation point using an aquarium light. The bigger worry should always be providing enough light, not just for survival but for good growth. Only continuous growth will result in continuous nitrate and phosphate removal! To achieve this--maximally--you’ll want to be sure that your seaweed bed is illuminated not only at the surface but all the way through to the bottom. This usually requires at least as much intensity as one might use to grow SPS corals!
In addition to high intensity, try to get a light that is designed specifically for plants. These types use only red and blue lights (plants generally don’t use other spectra) as to maximize the efficiency of the
fixture. Thus, while they look a bit unnatural to the eye, these lights promote the highest growth rates for your plants.
Finally, one big advantage of using a light fixture customized for refugia is that their housing is typically very compact. They might also have extremely adaptable mounting/positioning options. This means
that you’ll be able to fit the light into a small area (e.g. within cabinetry) and spotlight the grow space exactly as you desire!
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