Turning On The Light?
Fluorescent lighting in general is the ideal lighting for aquariums with the exception of Metal Halide lighting for reefs and fast paced planted tanks. As fluorescent technology advances, the trend is to produce thinner diameter bulbs which emit more light (lumens) per watt consumed. From the bottom up of the efficiency scale the list would look something like: T12 - T8 - T6 - T5
Compact fluorescent bubls are made in both T6 and T5 diameters, they are “compact” because they are either bent in half or spiraled to occupy less space. They come in both “self driven” versions, another words with the ballast built in just like the spiraled CF bulbs you would buy as replacements to regular screw-in bulbs, and also in bulb only configurations which require the use of an external ballast just like a regular straight fluorescent tube. The advantages of all this is efficiency, more light per watt consumed.
As far as what’s best in terms of spectrum, PAR and other plant related specs, those depend on the bulb itself and not the diameter or technology used. Full spectrum, 3~5 phosphor bulbs in the 3500- 8000K range are usually preferred for plant growth.
As a final note, there are some differences in quality and power factor between ballasts. The ballasts found in self-driven bulbs as the spiraled ones are typically cheap and don’t always last as long as the bulb itself does. A quality ballast on the other hand can further increase the light output, bulb life and spectrum quality of the bulb. There are also far better choices in bulb types and spectral outputs when shopping for standard linear or compact fluorescents which are not self-driven, just take a walk down the lighting area of your local fish store to see what’s available. Linear bulbs are also easier to redirect using reflectors, “bulb restrike” is a common concern with people trying to get as much light as they can into the tank when choosing between compact fluorescents and linear bulbs. Linear T5 and HO-T5 (High Output) are the most common amongst enthusiasts, however they can be “too much” light for some setups which is becoming a more common problem today than not having enough light…
Here’s a home made light fixture that uses screw-in compact fluorescents: http://www.gpodio.com/posts/HoodUnder.jpg
Hope that helps Giancarlo Podio, LMD
Category: Philippines Internet Koi Society
