Let There Be Light!

Ever want to control the sun?

I know I do living in the Northeast this time of year! I can just imagine, on a brisk winter day, typing in a computer code, and WHAM! more sun.

Well, guess what! I have the power (over my aquarium, anyways).

Throwing around the word Reef (when talking about an aquarium) means that there has been a lot of thought put into light decisions.

Why?

Well corals, as well as some additional animals (such as clams), are photosynthetic. They need the right type of light in order, not only to flourish, but to live. While some corals have the ability to catch food on their tentacles, they receive most of their energy and nutrients from light. This occurs with the help of the symbiotic and photosynthetic algae called zooxanthellae. Zooxanthellae live within the "flesh" of the coral, and are also the main component of the color the coral exhibits. Naturally "wild" corals require sunlight through clear and shallow water.

So to move these animals into a confined tank, we must provide pristine water and high quality light.

Water is easy as long as you perform your partial water changes (PWC) and have a good protein skimmer.

So let's take a look at the lighting system possibilities:

Fluorescent, Normal Output / Compact  Lights - Good for Fish Only With Live Rock (FOWLR) tanks. Fish do not need much light, and amping up your light in this type of environment can cause issues with algae growth.

Fluorescent, Very High Output / T5 High Output Lights - Still acceptable for FOWLR, but these lights will also allow the growth of some soft corals (depending on depth).

Metal Halides: MH -  The classic choice for most reef keeping enthusiast. These produce a lot of directed light under their specified location. All types of corals can grow under these lights. They produce a high photosynthetically active radiation (PAR) value - a value that is used to determine the strength of light at a specific depth of water.

The negatives of Metal Halides:

• They run very hot and can heat up the aquarium water.
• They burn out quickly and need to be replaced ~ 6 months for optimal lighting
• They use lots of electricity and have a high monthly electricity cost

Light-Emitting Diode: LED - Traditionally used in aquariums as blue "moonlights", these light fixtures are now being used by reef aquarium enthusiasts for all of their coral needs. These are energy efficient and produce little heat. LEDs also provide as much or more PAR than MH.

The negatives of LEDs:

• They are the most expensive purchase option
• They are relatively new, and reef aquarium purist are not convinced they work as well as MH

I decided to go with a full programmable LED unit. It has 48 bulbs that are 3 Watt CREE LED bulbs. The unit contains 16 Clear White Full Spectrum Bulbs (10,000-20,000K), 16 Actinic Bulbs 420-460 nm (a popular wavelength and "bulb type" that is beneficial for coral growth, and 16 Blue Moonlights 453 nm.

Each type of light it programable for both time of day they are on and intensity they are running. The moonlights also run on a 28 day lunar cycle. This cycle breaks the year up into four, 7 day, segments. Each one of the segments changes the intensity of the moonlights.

Daylight

Night Time

These lights have a Par of ~500 at 24" of saltwater depth. This should be more than plenty for all types of corals - from softies --> LPS --> SPS - as well as clams! I can't wait to fill my tank with all of these animals.

What are the different types of corals I'll put under my LEDs? You'll find out soon... next up, coral varieties!