# Why do some people diffuse their light? And how?



## Gizmo

I've heard about using egg crates, but why would you want to use them? What's the reason for diffusing light into the water rather than beaming it directly in? Aren't there heat buildup issues using egg crate?


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## mec102778

Not sure why there would be heat build up. I think egg crate is used as an alternative to a canopy or glass top to stop jumpers from making it out of the tank.


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## jrman83

Plastic is a heat insulator. Shouldn't be any heat build-up. Never heard of it being used as a light diffuser in an aquarium, but it is what it's used for in big fl light in things like office spaces. That stuff may not actually be egg crate, but same diff.


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## Gizmo

I had heard of people trying to better emulate natural diffused daylight, and made mention of using egg crate to do so. Glad to hear there's no worry about melting the plastic


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## jrman83

[email protected] said:


> I had heard of people trying to better emulate natural diffused daylight, and made mention of using egg crate to do so. Glad to hear there's no worry about melting the plastic


Oh, make no mistake, my T5HO lights would burn through that stuff in one night...but you have to use your head and provide some separation. T5HO bulbs are weird...put your hand just 1/2" away and you feel some heat, but not overly so...touch it and it will light you up.


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## WhiteGloveAquatics

I got a 65w daytime heat bulb for my red ear and its right on the egg crate, doesnt even heat the plastic up, but even off melted thru the top of a 36" striplight.

I had them to stop jumpers but diffusing the light worked well with keeping the brightness down as my discus dont like bright lights and I have 640w above my tank.

Yes T5HO's get HOT right under neeth them. I have to raise mine about 2' to be able to work in the tank with the light on. Ive even gotten redness that lasted a couple days on my right shoulder blade when I got within an inch of the bulb


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## automatic-hydromatic

I assume the idea behind using egg crate as a diffuser is to make the light spread more evenly over the entire tank, but I never noticed a difference with or without it as far as that's concerned

I used it for a while to keep frisky fish from taking a leap out of a tank, but after I hung the light up higher and got it off the tank sides, I made a plexiglass hood to cut down on the loss of water due to evaporation


my dual T5 fixture sat about 2" above the egg crate, and it didn't even get it warm














wow that's an old picture... but it's about the only one I have that shows the egg crate well enough


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## WhiteGloveAquatics

egg crate cuts down almost 40% of the light coming in the tank. all that plastic relates to surface area and put it all together and you have that much LESS light penetration, the light bounces off the egg crate and back to the reflector and starts all over again.

Lumen meters work great for this. I went from egg crate to actual plexi tops to stop this. as my plants were showing signs of light distress.


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## rtbob

As to why you would want to diffuse the light it is because some species of fish prefer it over bright direct light.

On my 20g I stuck long vines (plastic) with silicone under the glass on the aquarium lid.
The single 15 watt florescent light sits on top of the glass. This gives the apperance of floating plants and diffuses the light with out any heat build up.


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## Gizmo

I've got plenty of greenery (lotus pads, anachris stalks, riccia and frogsbit) at the surface to diffuse the light for my fish. Think I'll just stick with that. Thanks guys!


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## beaslbob

mec102778 said:


> Not sure why there would be heat build up. I think egg crate is used as an alternative to a canopy or glass top to stop jumpers from making it out of the tank.


+1

And to hold the fixture as well. At least when I use round clip on spot reflectors. Just lay them on the egg crate.


my .02


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## mec102778

beaslbob said:


> +1
> 
> And to hold the fixture as well. At least when I use round clip on spot reflectors. Just lay them on the egg crate.
> 
> 
> my .02


That's what I'm thinking of doing for my 10Gs, round reflectors with CFL bulbs sitting on the crate.


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## jeep96

Has anyone ever seen a tank that is lit from underneath? With a diffuser plate to spread the light evenly across the bottom? I think it would be pretty cool. I wonder if there are any products out there.


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