Metal Light

Posted in January 2, 2009 ¬ 2:15 pmh.adminNo Comments »

Metal Light
What fish/corals can I put in a tank with metal halide light, that i CANT with power compact lights?

Whats the main diffence between the 2 lights

For fish, it wouldn’t matter – they don’t use photosynthesis to make their food.

There are a lot of differences between compact fluorescents and metal halides, and not all differences relate to what’s in your tank. But MH lights are more intense and will penetrate deeper into the water. They also produce more of the “shimmery” light effect so it looks like you’re actually in the ocean underwater. So MH are best for deeper tanks, and those with corals that have higher light intensity needs (small-polyped stony corals especially).

Some of the other factors about MH that you should know is that they also give off ultraviolet radiation, just like natural sunlight, so you could be sunburned if you spend too much time exposed to them. The lights should be shielded from everything except the tank. They also cost more to run, because they have a higher power usage. And they also produce more heat, so they may make it necessary to use a chiller on the tank so the water stays within the temperature tolerance for corals (they shouldn’t be exposed to water temperatures over 84oF). Metal halides also are more expensive to buy, because they require a special glass that allows the UV rays to pass through. And don’t consider just the cost of the fixtures here, because the lights begin to lose some of the intensity in the spectra needed for photosynthesis at around 6-9 months, so all the lamps should be replaced at least yearly, even though the lights haven’t burnt out yet.

This link, besides going into a lot more detail on the technical aspects of light (lumens, wavelengths, color temperature) does a little more comparison of the different types of lighting systems available (see under bullet #8): http://www.americanaquariumproducts.com/Aquarium_Lighting.html