# Bulbs?



## mahamotorworks (Nov 7, 2006)

Ok I have read the stickies and done a lot of research but I need some personal from experience info. 

I have a 29G tank with a DIY Canopy and 24" floresent fixture, it has 4 bulbs. I am looking into buying some new bulbs for it. I currently have 2 5000K and 2 2700K bulbs. I went looking for a 10000K bulb, all of the LFS here jumped from a 4700K to a 18000K bulb. I found some Phillips F20T12/D Alto Bulbs that are 6500K, at Lowes. Would it be in my best interest to buy the Phillips bulbs? Or should I continue my search for a 10000K bulb online? I am looking for what is best for the plants. I can deal with the color that a bulb puts out I lived with 2700K for a couple of months now. I know I want to keep one 2700K bulb over the tank. 

I just want to know what you reccomend.

Thanks

MAHA


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## darkfury18 (Apr 28, 2006)

I'm using 2 philips 6500k over my 50g without a problem, although they do have a greenish tint to them which i like anyways


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## Yeaulman (Jun 23, 2005)

Where did you pick up your philips 6500K? are they 55W or 65W?


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## Newt (Apr 1, 2004)

mahamotorworks said:


> I am looking for what is best for the plants.


Lighting for a planted tank should not be chosen on color temp alone. It is true that 'full spectrum' bulbs are referred to as bulbs between 5000 Kelvin (K) and 6500 K and are best for planted tanks. Yet this does not indicate what type of light (wavelength in nanometers) the bulb is actually emitting. If you want both good leaf development and compact growth (blue light) and stem elongation and color (red light), you need light in both the blue and red spectra for photosynthesis.

If you want to optimize plant leaf development (blue light) and stem elongation and color (red light)

You need a mix of blue and red for your plants, and green for you (brightness as perceived by humans). If your lighting looks extremely bright and your plants seem ultra-green, it means that you have lighting that outputs strongly in the green spectrum. Do not equate this with good lighting for your plants, because plants don't use light in the green spectrum for photosynthesis.

For green plants the lighting peaks that are most important:
chlorophyll-a: 430nm/662nm 
chlorophyll-b: 453nm/642nm 
carotenoids: 449nm/475nm 
Red pigmented plants use more light in the blue area of the spectrum.

Beyond choosing lighting that is optimal for photosynthesis, as above, you should choose lighting with the color temperature that best suits the aesthetic goals of your tank. So, don't obsess about color temperature beyond how you want your tank to look. From a color temperature standpoint, blue-colored light will enhance blues in your fish. Green-colored light will make the tank look bright to humans and enhance the green color of your plants. Red-colored light will enhance the reds in your fish, and any red plants.

I have attached some jpg's to help understand lighting and how plants react to it. I have found it best to provide a mix of lighting to a planted tank. The GroLux bulb is perhaps the best plant bulb available but it has very little green light so the visual effects of your tank will look dim and purplish. Yet if you add some other lighting such as a Philips 6500K the effect is more pleasing to the eye and still beneficial to the plants.


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## ruki (Jul 4, 2006)

Also, note that the K rating is something of a marketing driven misnomer. Fluorescent bulbs have multiple peaks where a true K rating (this is really a Physics term) would have a single peak with a continious curve. 

So, just get spectrum charts of the bulbs you are interested in and compare them with the charts Newt suplied above.


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## Newt (Apr 1, 2004)

The attachment below may help with what Ruki is saying. This is because the Kelvin color designation of a particular bulb is not always true to the black body locus line as shown on a CIE Chromaticity map. This is why some 5000K bulbs look yellow and others white, especially when trying to compare a linear fluorescent with a CF or MH.


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## Left Coast DJ (Nov 16, 2006)

So what readily available brand & bulbs are best for a planted tank?

DJ


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## Newt (Apr 1, 2004)

In CF/PC, not much that is best for a planted tank. There is the Philips PL-L series and I find that the PL-L 950's are decent; they are 92 CRI. Stay away from the coralife as they have a prominent green spike in the spectral output. Sylvania has some Studio CFs: one is 3200K and the other is 5600K (I'm not at home so I cant post pictures of the spectral graphs). A lot of people like the GE 9325K even thou its only 67 CRI.

When you get into linear N.O. fluorecents there are lots of good choices. I recommend a mix of bulbs. There is the Sylvania GroLux, Interpet Triton, GE 9325K, All Glass 8000K, Philips C75. I havent delved into the T5 TEK linears yet but perhaps Ruki has insight on some good ones.

I'll try to get back tonight and post the spectral graphs for most of these.









Triton









Philips C50 and C75









Philips PL-L 950









Sylvania GroLux









GE 9325K









Coralife 6700K









All Glass 8000K









Sylvania Studioline 3200K and 5600K CF bulbs


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## ruki (Jul 4, 2006)

Lots of bulbs will work OK. Some work better than others and some look better than others.

Since my electricity bill is getting too high, on some of my tanks I'm reducing costs by replacing magnetic ballasts with electronic, and moving to more efficient and inexpensive tubes.

Diana Walstad's book has a chart where she shows that a vitalight and cool white gave excellent results. I get good results with a stock 6500K Sylvania Octron (super efficient!) tube combined with an old fashioned GroLux. I just ordered some ZooMed plant bulbs to replace the energy wasting thick T12 GroLux tubes. The Zoomed tube looks like it has a decent spectrum.









I have a couple T5 Coralife fixtures for low to medium light tanks. The Coralife 6700K bulb is better compared to the Coralife plant bulb. I plan on using cheaper 6xxxK tubes when I put together an order for T5 tubes. (Why spend all that money on a tube with a big green spike?)

For T5HO, I use a mix of tubes. GE 6500K are the cheapest at reefgeek and work OK. Mixed in is a more expensive 10000K tube for more colors. There should be more cheap T5HO tubes as time goes on.

There are fancier tubes that may do better, but how much better for the increased cost? If you are in a competition and want a special look, then the expensive tubes make alot of sense. But, for non-show tanks, it isn't really necessary.


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## Newt (Apr 1, 2004)

Ruki,

How about taking some pictures of similar tanks with the zoomed and a grolux and posting the results in a thread when you have come to some conclusions versus the two bulbs?


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## ruki (Jul 4, 2006)

Newt said:


> Ruki,
> 
> How about taking some pictures of similar tanks with the zoomed and a grolux and posting the results in a thread when you have come to some conclusions versus the two bulbs?


That's a good idea, but first I have to pick up another 48 inch long fixture to do the comparison.


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## Newt (Apr 1, 2004)

That's super.


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## Newt (Apr 1, 2004)

Ruki, how's the experiment going?


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