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question that's been kind of bothering me: how much do reflectors matter in light hoods? say you have two 55 watt bulbs, that's 110 watts. I understand that a good reflector can have 150% output, making it seem brighter than an unrefected 110 watts. but how does that effect plants? i'd assume even though it seems brighter, thats still only 110 watts going to the plants no matter what.

likewise, what about poor reflectors that don't do a good job - how does that effect plant growth?

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Back in the saddle!

I guess it comes down to the watts on the top/sides of the tube going to waste otherwise... if a tube is giving off 55 watts of energy, that's over the entire tube surely?

"catching" some of this "wasted" light and redirecting it downwards means it's getting into the tank (albeit at a reduced intensity) when it would otherwise be lighting the walls/ceiling (or the top/side of the inside of the hood) a reflector's "angels" are specifically designed to get this light going "down" (not to mention an exposed tube on top of a tank can be very visually distracting if it's not in a hood (presuming one is using a shop light/bare baton type set-up like your's truly)).

Also: if it's a plain white reflector internally, taping on aluminium foil (shiny side down) ups the reflectivity a good deal IME

Dex

Last edited by dextroze at 22-Oct-2004 13:41

The only things that matter are brightness and light spectrum. Everything else is intended to indirectly affect those two. If I were to change out a perfectly black reflector (absorbing all light) and put in a perfectly reflective reflector of the right shape (reflecting all light into the tank) then my plants would get twice as much light and possibly be much happier.

Dextroze wrote:
...if it's a plain white reflector internally, taping on aluminium foil (shiny side down) ups the reflectivity a good deal IME.

Yes, yes it does. The best reflectors, themselves, are polished metal of some sort, acting as mirrors. A perfect reflector would actually be shaped as a parabola, for mathematical reasons, but curved surfaces are probably far too costly to manufacture through metal machining.

Last edited by Silverlight at 22-Oct-2004 13:47

ok, makes sense...

I have a 110 watt hood, but the reflector is pretty bad and I noticed that, when it's on, my tank doesnt look brighter than my old 60 watt hood. are you all saying that my plants arent really recieving 110 watts of light? if so, how can i correct this? i guess i could gut the whole system, but would aluminum foil really work?

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Back in the saddle!

Silverlight (what a fitting name for this particular thread ) :

Yep, a parabola catches the rays at the right angles from any given section of the tube so it gets reflected down (presuming the tube is also mounted precisely lol).

I'd actually be interested to see a study on the "real world" reflectivity of parabolas vs. regular "two angle" or curved reflectors.

(Actually, that might not be a good idea, cause then I'd just wish I had one lol)

nowherman6:

I have a feeling the "watts per gallon" rules take into account a level of light "loss" from the system, so I wouldn't be too worried... foil does work a treat though (and for a few cents, gives you the biggest "bang for your buck" as an upgrade option)

Dex

Last edited by dextroze at 22-Oct-2004 14:07

"Silverlight (what a fitting name for this particular thread )"

LOL.


thanks for the info, dex. like i said, my reflector just leaves the tank looking on the dull side, so i'd like something to brighten it up and utilize the brightness of the bulbs better... i would have spent big $$ on a CF unit with better parts, but i'd rather save up for a good CO2 unit since DIY wont really cut it on my 46 gallon. besides, i don't mind having a frankenstein light setup, as long as it gets the job done.

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Back in the saddle!

I've had tinfoil in the hood of my 29g for quite some time, and it works wonderfully. It's really easy to install and is great for your plants. I really reccommend it

A good refelector will make the maximise the use of the light the bulb is emitting, by reflecting it down into the tank. The claims by some maunfacturers that they "double intensity" is a bit bogus. They simply redirect light, that would otherwise be bouncing away from the tank, downwards.

Actually foil may not be as efficient as you think, it has a tendency to reflect light all over the place. A much more efficient method and just as easy as cheap is to paint the inside of the hood with a white gloss paint.Does a much better job

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