Many aquarists commonly use the (drop ceiling) building material known as "egg grate."

This intersecting lighting grid is designed for drop ceiling installations in places where light fixtures are installed. Aquarists use egg grate to cover their aquariums as they block little light from above and nicely keep most all fishes from jumping out at the same time

But did you know that there is a top side and a down side to egg grate?

More accurately, there is a spread side and a focus side. That is to say, the interior partitions of the grid are actually tapered to a narrow on one side for the purpose of spreading or focussing light downward, depending on position.

One side measures approximately .07 in thickness while the other measures only .05

So if you are installing egg grate in an office and you are looking for optimizing light spread and energy consumption/efficiency, you'd naturally want maximum spread of light (the tapered side facing downward).

But we want to focus precious aquarium light (expensive to produce!) downward to get as much of it into out aquarium as possible (tapered side up). If you have an aquarium in a dark living room, for example, you may notice that light shines out from the aquarium glass and onto the floor. That is wasted light! But if you put the egg grate over it and focus the light downward, you will notice the light does not spill onto the floor anymore! Remember... tapered side up for aquaria.

The other caveat is that you want to capture the light before it gets a chance to spread out from the fixture itself... so the egg grate must be rather near to the lamps. Fluorescents are easy... they must be close to the aquarium water surface to be remotely effective in the first place (within 3") and the egg grate can be placed safely between them. But metal halide/halogen lamps run very hot and the egg grate can melt, like other plastics. Keep the egg grate several inches away and use cooling fans for hot lamps. That's no inconvenience here because you will need to keep metal halide lamps farther off the surface than fluorescents anyways, and they all typically benefit (literally affecting the color and quality of light) from running cooler (with ans) regardless of egg grate use or not.

FWIW

kindly, Anth-





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Anthony Calfo

Paul... does the phrase "beat like a red-headed step-child" mean anything to you? Hmmm... just curious. Er... put another way, "the numbers never lie." A light meter placed under your lamps at say 5-7" off the water surface and then taking readings at even the very surface of the water (before going under where your corals will be/need the light) will be very disappointing to you Despite quality of light form many fluorescents, what they lack is intensity. They have a weak punch. And anything over 3" off the surface of the water is really quite a waste of light. Its staggering really. If you have the funds in time to buy another cool toy...do check out an Apogee Quantum light meter (search this forum for a thread on it or see it in the list of discussions under "fav links.." atop this forum. Frankly, my friend... fluorescents over 3" off the water are very poor for keeping zooxanthellate animals alive in aquari. I am sure these need to be lowered considerably.

If you ran a comparison of a single 175 watt metal halide over water at depth versus two 100 watt VHOs even (total 220 watts of light), the 175 watt halide will significantly outperform the fluorescents at depth. They have the intensity... and as such allow you to keep more corals, plants, algae for the same or less light used in that aquarium. The MH lamps also last longer too. I do use VHO on some aquaria because i like the color and I accept the limitations. But MH is hands down the best value in light IMO

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Anthony Calfo

http://www.marinedepot.com/FORUMS/Topic24408-13-1.aspx

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Anthony Calfo

-Sam

Anthony Calfo