Watts, bulbs and electricity

[moze229]

I wanted to share with people what we need to keep in mind about light and light fixtures over aquariums. This is probably already common knowledge, but for some reason all of our brains stick to using "watts" as a unit of measurement in describing light brightness. Not just in aquariums, but for everything else as well. This is not an attempt at describing how to determine what type, and how much light you need for your setup - Hoppy has already done a superb job of that here http://www.plantedtank.net/forums/sh...d.php?t=184368 and I don't have the knowledge to compound on that subject anyway.

Back in the early days, people used "watts" as a term to describe light brightness. And during those times, that was a fine thing to do because there was only one kind of light - incandescent. In everyday conversation, work environments, and everything else, you could tell someone how many watts a bulb was and they would have a pretty good idea how bright it was.

Today, there are many different types of bulbs, from fluorescent, halide, LED, incandecent, power compact ( a type of fluorescent), halogen, etc. They may run from AC power or DC power. And finally, as we all know, they may have different spectrums. All of these factors can determine the "brightness" of any given bulb, regardless of "watts". The watt rating of a bulb simply tells the consumer how much electricity a bulb consumes - that's it. Needless to say with all of the options in bulbs these days, using "watts" as a description of brightness is futile.

"Then why do all of the bulb manufacturers still use 'watts' as a standard description of brightness to consumers?", you might ask? Well, they do and they don't. Using the electrical consumption rating of any given bulb as a description of brightness amongst society has become so ingrained that it's hard for even the manufacturers, sometimes even people that are experts in the industry to get away from using the term. It's just the way we have bought bulbs, and continue to buy bulbs today. Have you tried to go buy one of those new CF bulbs and get confused about which one you need because all of the wattage ratings went way down? I do. We need to get away from this.

I don't know all of the science behind lighting, but I do know that using "watts" is no longer valid. "Lumens" would be a good start. This is because lumens tells us the amount of light that a particular bulb produces rather than how much electricity it consumes. If you look close enough on most bulb packages it will give a lumens rating. Even lumens doesn't give us the whole story, but it would be a much better unit of measure for brightness than "watts" and it would be more than sufficient when determining lighting needs for an aquarium.

Remember, the next time you are shopping for bulbs or particularly, trying to figure the correct usage of lighting for your aquarium - do not use the bulb's wattage rating as an indicator of brightness - at least not the sole indicator. It doesn't work. An example of this can easily be illustrated using LED fixtures. I have a halide fixture over my reef tank that is rated at 150 watts. I have another LED light over another reef tank that is 72 watts. At full power, the LED fixture will output a little over 1.5 times the PAR as the halide light. It uses less than half of the electricity of the halide bulb.

STOP THE WATTS MADNESS NOW! : ^)