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This is not a super big deal of for a question but here goes.

If 6700K is ideal for plants then why to bulbs like Aqua-Glow run 18,000K? Is it something to do with the type of lighting? The florcents are much low watts that most other types of lighting.... Just wondering how that all works. Thanks everyone!

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

Hi,
Personally, I'd never use 18K lights for a freshwater tank.
They simply don't need that kind of light. It's more
designed for Saltwater tanks with inverteberates in it.

It is also a kinda touchy subject as there are folks who
would swear by it. Aquarium Fish magazine ran an article
about lighting in a freshwater planted tank you might want
to look that up at their online site.

Heres a nutshell course on freshwater lighting...
Plants prefer light in the red and blue parts of the
spectrum. So, generally speaking they like light around
4-5000K and 18-20,000K. However, if you were to look at
a tank that has 5000K bulbs, the tank light looks yellowish
red. If you look at a tank that has the 20,000K bulbs it
will have a bluish tinge to it. Both kinda wash out the
colors of the objects (plants or fish) that you are trying
to appreciate. Very few folks will run only 5000K bulbs
or only 20,000K bulbs alone. Most will also run a bulb
that is rated around 6700K so that the effects of the
highs or lows, are not noticed. The "Color Rendering"
(How well a red looks red, or green looks green) of a 6700K
bulb is more true to the color being looked at.

We had one person on FP write that when they put 6700K
bulbs on their tank that the greens were too bright and
actually changed the bulbs out.

6700K is a great place to start for viewing both plants
and fish, then go up or down depending upon your personal
view point. They are less expensive than the so called
"Plant" speciality bulbs, and are readily available at
nearly any hardware store. Just purchase a bulb that is
rated at DAYLIGHT or SUNLIGHT, not the "Cool" or "Warm"
types.

We can chat more if you'd like...
Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

We will have to talk some more but I have to get to bed now. Thanks for getting back to me!

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

Glo series bulbs don't follow the general guidelines of aquarium lighting. They use a different ratio of spectrums and so they say 18,000k but actually look red-purple instead of blueish. They grow plants great in my experience but may make the tank look odd. On my 90g I have 80w using 2 of the glo bulbs(can't remember which ones) and I have them come on in the morning and evening. It looks sort of like sunset and sunrise. The plecos love it and always come out then. For my main lighting though I use 10,000k bulbs. While most people think they look more blue and washed out I prefer it to lights in the 6,700k range. After using almost all 10,000k bulbs since I bought my fixtures with saltwater bulbs in them the 6,700k still looks too yellow to me. If you've been using glo bulbs or bulbs that aren't full spectrum such as warm or soft white then 6,700k would probably look far less yellow or colored and more white. It's partially a matter of preference provided you are giving the plants all spectrums of light especially lots of red and blue. The 6,700k, 10,000k and glo bulbs will all accomplish that but your tank will look quite different depending which you use.