Author Topic: MCMAC Presentation: James Fatheree - A Look at Aquarium Lighting  (Read 1781 times)

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Offline psa

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James Fatheree conducted systematic, controlled measuring of light output from different types of lighting to see how they compare in real world environments--that is, in standard aquariums, filled with water, using different reflectors and tank backings.

Reflection from the glass can make a big difference.

Painting the back of the tank (even blue) can decrease the amount of light at the bottom of the back of the tank by as much as 34% due to loss of reflected light.  Taped on plastic does not decrease light reflection at all, though, because of the way reflection happens at the interface of the glass and air.

It is very important to keep the glass clean for optimum light capture.

Simple single reflectors on fluorescent fixtures can more than double the light output, even right under the middle of the light itself.  Individual reflectors on each fluorescent bulb can triple the light in the tank.

Bulbs work best at their optimum temperature. T5s should be about 95 degrees for highest efficiency.  VHOs at 75 degrees.  Proper ventilation is imperative, and housing together with metal halides can greatly harm efficiency.

According to his research with a light meter in various people's healthy, thriving coral tanks, most corals will thrive under 110 PAR, which isn't much.

Almost any 4-bulb T-5 systems can light all of an 18" wide tank to over 100 PAR at 18" under water, which is enough, again, for most corals.  Many 4 or 5 bulb T-5 fixtures can provide over 200 PAR at 18".

The tested LED fixture didn't perform any better at 18" under water than the 4-5 bulb T-5s with good reflectors, but they required much more electricity.

For concentrated intensity, though, nothing beats metal halide, which easily doubles the output of T-5s, especially at the center.

From the Q&A:
Clarity of your water makes a huge difference in light transmission, as well.
« Last Edit: July 20, 2009, 02:34:37 AM by psa »
Years ago my mother used to say to me, she'd say, "In this world, Elwood, you must be" - she always called me Elwood - "In this world, Elwood, you must be oh so smart or oh so pleasant." Well, for years I was smart. I recommend pleasant. You may quote me.