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Altanta Reef Club
10 June 2003

Our presentation by host Doug McIntyre concerns lighting. Doug began his business as a way to help finance his own reef tank at a time when he was taking flight training. He now has 19 styles of light fixtures for sale, ranging from 14" to 72" housing VHO, PC, T-5, and halide lamps.

Our reef lighting systems rely on ballasts to ignite the bulbs and there are essentially two distinct styles. The magnetic type is the older technology using a transformer [heavy metal with wire windings] and a capacitor. In the magnetic class there are two different types of ballasts, the standard core and coil ballast which uses a capacitor and transformer and a pulse start unit. The Pulse start ballast consists of transformer, capacitor and starter. The pulse start ballast is used mostly on European bulbs. There is a special ballast for the Iwasaki bulbs which have the igniter inside the bulb. Magnetic ballasts in general are heavy and generate considerable heat, but are less expensive [ $60 ] with warranties lasting several years.

The electronic ballast is much smaller [ 3" x 10" ] and gives off little heat. They also can cost more than double the price of a magnetic ballast. The benefit of a high frequency allows the electronic ballast to be more versatile in the range of bulbs it can strike / fire / ignite / burn. In fact the 250-Watt IceCap HQI solid-state ballast runs about $160 and can fire any bulb. CoralVue electronic ballast is currently being imported into the US and distributed by AquaticCo (couldn't help the plug) it can fire any mogul base bulb. This ballast will be significantly lower in price over the IceCap ballast

Many corals have algae inside their bodies and these zooxanthellea absorb the sun like any plant and produce sugars, which the coral uses as food. PAR or photosynthetic active radiation is a measure of how useful the light is to the algae. The length of a light wave is measured in nanometers and we find the range 400-600nm, a blue color light, to be most useful for our corals. 6.5K or 6500 Kelvin is closest to the wavelength of natural blue sky and shallow reef sunlight. Ironically, the bulb which benefits SPS and LPS corals the most is the 10K HQI bulb, which has a whitish yellow-blue color. The second best bulb is the Iwasaki 6.5K bulb, which gives off a yellowish-green color.

HQI bulbs are double ended metal halide bulbs in 150W, 250W, and 400Watt with Kelvin color temps of 10K and 20K. Used with a polished aluminum reflector they can achieve effective simulation of sunlight on the reef. Both German and Japanese bulbs are available. It can take up to 100 hours of use to stabilize the bulb and at the end of it's 1-2 year useful life the color will tend to shift towards the red spectrum.

Another form of lighting is the fluorescent bulb represented by VHO [ very high output ]being the established technology with the most variants available. T-5 bulbs are the newest arrival to the American market. These newer 5/8" diameter bulbs can also produce considerable light by squeezing many bulbs into a light fixture. T5 lights are HO lights or high output. There are also power compacts, which bend the bulb into a U-shape for more light in a given space. All three bulbs are available in actinic, which is an ultraviolet blue color. This actinic light is much admired by reef enthusiasts who dive as it comes close to the light color seen underwater and the ultraviolet [black light] fluoresces the corals into glowing luminescence.

Some of the latest ideas of aquarists concern random shifts in lamp intensity to simulate cloud cover and LED night-lights simulating moon cycles. The end goal is to maintain our corals in optimal health and lifespan. If lighting can help create spawning events we know the corals are satisfied with their home. Doug's preference for lighting would be an electronic ballast from IceCap for the double ended metal halide bulb 250W 10,000 Kelvin and the use of actinic fluorescent bulbs.
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