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Re: DIY Reflector
First thanks for the reply.
> Previously I had assumed that the reflector would similarly help an
> aquarium. From what I _now_ understand, without a reflector, some of
> this stray light would reach the plants by being reflected off the
> glass. So although I still suspect the reflector would provide more
> lumens to the bottom of the tank, I don't know if the rule of thumb is
> quite the same for an aquarium as it is for an office. My apologies to
> Bob and anyone else to whom I previously wrote regarding reflectors. My
> previous assumptions appear to be at least partially wrong. I am
> familiar with reflectors, but unfortunately only as they apply to human
> environments. I'm still learning about how they work in an aquarium.
Actually, Wright Huntley has written several messages concerning
an aquarium as a light tunnel. Essentially, the perfect scenario is an
empty tank, crystal clear with an all light absorbing bottom and RO or DI
water. In this case, the aquarium acts as a light tunnel and all
available light eventually makes it to the bottom (assuming also perfectly
reflectant glass sides). However, material in the water, yellowing,
plants, protein skum, etc. all block a lot of this light which is why
many people recommend a lot of extra light for deep tanks... it is not
that the light can't get there, it is just that there is too much junk
in the way.
Finally, algae on the glass blows a lot of the figures since this
does not reflect the light, so you still might benefit the hobby to be
able to direct in such a way that the light largely goes straight down
instead of bouncing all about. Keep going.
> The second point is in regards to the white paint vs. polished metal
> discussion. I've heard a similar argument from a lighting consultant
> about their 'reflectance' being almost the same, but haven't seen any
> figures to back it up. Another thing to consider which you may have
> observed is that white surfaces reflect light in a diffuse manner. That
> is, the light striking the reflector at a given angle is reflected in
> several directions. On the other hand, a mirror reflects light at an
> angle directly related to the angle at which the light strikes the
> mirror. That's why you can see yourself clearly in a mirror, but not on
> a piece of white enameled metal. Any physics/optics experts out there
> will hopefully clarify or correct what I just wrote.
Yes, this was understood, but that the light intensity, though
scattered was nearly as intense. Eric Olson was the person reference
for this one. Eric, you still about?
> P.S. I'm not sure if this is what Matthew is referring to, but there
> are ballasts with a higher 'ballast factor' that provide a higher lumen
> level from a given fluorescent lamp, at the cost of greater electric
> consumption. Ballast factors are applied directly to the lumen output
> of the lamp, if I'm not mistaken. E.g., 3000 lumen lamp x 1.2 ballast
> factor = 3600 lumens.
Yes, thanks for a more lucid response than mine.