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Discussion Starter #1
Went down to my new favorite LFS - Tropical Haven, and picked up a 20" Hood and a 15 watt Aqua Glo bulb for it, it was on sale and the box said the bulb would work fine for low light req. plants. 18,000k and 290 lumens.

This is the first time any lighting has been used on the new tank, I noticed that the goldfish and craw don't like the lighting much, probably not used to it?
 

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The 18000K bulb is not a plant bulb, it is a bulb for a saltwater tank. If you can exchange it for one closer to 8000K, it will work better for plants.
 

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Discussion Starter #3
Ah dang, thanks for the response. I'd hate to get plants in this tank after it cycles and have them not do well!

The box said that it was a good bulb for planted tanks and fish color.

Sigh.

Thanks again!
 

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Check the numbers again. at 18000K it is a way shorter wavelength spectrum than sunlight would be. Noon sunlight is actually about 5500K but that looks a bit yellow to most people.
 

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Discussion Starter #5
I called the LFS, and they said that an exchange would be fine. Thanks for the heads up on the bulb. Without the correction, I'd be stuck writing a new thread titled "my plants are turning brown!"
 

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Discussion Starter #6
Well I went to exchange the bulb, and as usual, they were extremely helpful. I realized that even though the particular store that you are using is knowledgeable as a whole, there is always someone there who knows a little bit more than the other about a certain aquarium subject.

I picked up a 15w 6700k Life Glo Full Spectrum bulb. I also jumped the gun a bit and put the driftwood/java moss in. Notice my temporary "crawdad keeper" installed behind the lighting hood? Yeah, found one of these guys in my bed yesterday so I cut up an old storage bin lid and modified as needed.

Pics:





 

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Warning this may be overly complicated but I wanted to add some of what I consider to be important information about lighting and kelvin ratings.
First off I am not disputing what Oldman wrote about the 18000K vs. 8000K as this is more often than not the case but biology hates rules.
If your not bored yet...

I would like to add to this that the kelvin rating of your bulb is not the whole picture in terms of the value of lighting for your plants. Most plants use light in both the red and blue spectrum for photosynthesis but do not use light in the green spectrum. Chlorophyll reflects green light absorbing best in the blue and has a secondary spike in the orange/red. This is why plants generally look green. In water the red wavelength is lost very quickly and many corals grow beneath the leval at which red light is plentiful, which is why most marine lights tend towards blue. In freshwater systems most plants grow high enough in the water column that they still recieve a decent amount of both of these. Many freshwater plants use secondary photoactive pigments that spike in the reds and orange wavelengths phycoerythrin and phycocyanin. Plants that use these pigments in large amounts will be those that look purplish or very dark green.
Here is a link to an image with the light distribution.
18000k aqua-glo image by alexmaoli on Photobucket

The hagen agua-glo 18000K bulb you initially had has a large spike in the orange/red and a moderate spike in the blue with very little output in the yellow and green wavelengths. The 8000K bulbs tend to have similar profiles as your 18000K aqua-glo but the main spike is in the blue and the secondary spike is in the orange/red. So this bulb is actually appropriate for many freshwater plants.

I hope this was at least a little bit useful and not too boring.
 

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Not boring but waaay over my head. I don't even know what kind of bulb I have or what I should be using. I bought a 75 gal tank, the glass hood, and a strip light. Guess I should have looked into it more.
 
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