# Best lights to display reds and blues



## charliebebop (Nov 17, 2010)

Hi There. I have a tank which I have just densely planted, and hope to add more colourful fish to. The hood which came with it contains two T8 fixtures, one for the front and one for the back. I have just ordered a Philips Aquarelle for the back to support the plant growth. I was wondering what kind of tube I should get for the front to best display my fish colours.

Now, the standard thinking would be for a natural white tube at around 5000K. However, my main 'colour' fish will be cardinal tetras and dwarf gouramis, both mainly red and blue. Would I be right in thinking that a tube strong in the red and blue spectra would cause these colours to reflect more, and hence be more colourful? In other words, should I get another aquarelle?

Thanks, any help appreciated


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## Byron (Mar 7, 2009)

With a planted tank, first consideration should be given to the needs of the plants. Briefly, for photosynthesis they require light in the blue and red colour of the spectrum. But it has to be sufficient in intensity and duration.

The problem with many (all of the ones I have seen) of the so-called aquarium or plant lights is that they are high in blue and red but too weak in intensity. As an example, the Aqua-Glo in the range manufactured by Hagen is about 1/2 the intensity of their Life-Glo 2. The other issue is appearance; while the blues and reds are highlighted somewhat, the tank takes on a purplish hue which does not show the true colours of plant leaves.

Scientific studies [these are referenced in the lighting article in the series "A Basic Approach to the Natural Planted Aquarium" at the head of the Aquarium Plants section] have shown that aquatic plants grow best under a combination of full spectrum and cool white, second best under cool white, third best under full spectrum and last under warm white. I should say that "full spectrum" can mean different things depending upon the manufacturer, as indeed can cool white.

Most of us here have found that a "daylight" light with a Kelvin around 6500K is the best. This has accents in the blue and red, but balances it with green for a true colour rendition of fish and plants. And i have found that the colours on my cardinal tetra really stand out with this light. You might be able to spot this in the photos of my 115g Amazon Riverscape under the "Aquariums" tab below my name on the left.

I have a mix of one 6700K full spectrum and one cool white on my three larger tanks. Your Phillips tube will probably be fine if it has a full spectrum with it. The slightly blue will be similar to the blue emphasis I have from the cool white.

Byron.


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## charliebebop (Nov 17, 2010)

Thank you Byron. The aquarelle is a 10000K tube that was originally designed for indoor gardeners and is apparently very popular with aquarists here in Europe.

So, for the second tube to compliment this and better show off the colours of the cardinals, you would recommend cool white or daylight? So I know what to look for, would you know roughly the kelvin of cool white?

Thank you again for your help


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## burnsbabe (Jul 15, 2010)

You might also give a look to the "Colormax" bulb that Coralife makes. I think they come in both T5 and T8. Whether they're available in Prague or not is another question.


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## charliebebop (Nov 17, 2010)

Yes, we've got some great breeders here, but we're a bit limited for brands. Kelvin ratings would help, and I can find the closest fit


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## Byron (Mar 7, 2009)

All of my tanks have tubes around 6500-6700K for the main tube; the "cool blue" effect comes from a tube with a higher K around 8000K-10000K. As long as you have the one 6500-6700K tube, the second "blue" will be OK, but without the red the blue promotes terrible algae.


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## charliebebop (Nov 17, 2010)

Thanks, that gives me a great idea what to look for


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## Mikaila31 (Dec 18, 2008)

Byron said:


> All of my tanks have tubes around 6500-6700K for the main tube; the "cool blue" effect comes from a tube with a higher K around 8000K-10000K. As long as you have the one 6500-6700K tube, the second "blue" will be OK, but without the red the blue promotes terrible algae.


Interesting. I use GE aqua rays which are a bulb supposably around 8000K. The package itself says 9325K which I would take with a little salt. I use these bulbs solely on my high tech tanks and don't experience alot of algae. I don't like the color of a lot of th 6500-6700K bulbs TBH. I do use them but not on my high tech tanks.
_Posted via Mobile Device_


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## Byron (Mar 7, 2009)

Mikaila31 said:


> Interesting. I use GE aqua rays which are a bulb supposably around 8000K. The package itself says 9325K which I would take with a little salt. I use these bulbs solely on my high tech tanks and don't experience alot of algae. I don't like the color of a lot of th 6500-6700K bulbs TBH. I do use them but not on my high tech tanks.
> _Posted via Mobile Device_


I actually use a combo, but didn't want to confuse further since he already intends to retain one of the others. On my 115 it is a 6700K Life-Glo 2 and a 11000K Lightning Rod Super Daylight. On the 90g a Life-Glo 2 6700K and a ZooMed Coral Sun which is high in blue and from colour appearance must be around 10000K. On the 70g I have a Life-Glo 2 6700K and a Phillips Deluxe Daylight which is a cool white.

I remember your (Mikaila) mentioning elsewhere about using high-tech to propagate your plants to sell. You might want to consider a combo similar to what I've mentioned. In an article in the July 1987 issue of FAMA, K. Richards reported a study of various spectrums of light with the identical plants (Elodea) and conditions; plants grew strongest (producing more oxygen) under a combo of full spectrum and cool white; second under cool white alone; third under full spectrum alone; fourth under warm white alone. This study is cited in Diana Walstad's book Ecology of the Planted Aquarium, with the graph (p. 180). The plants produced 47ml of oxygen in each 24 hour period under the combo compared to 38ml under cool white, and 25 ml under Vita-Lite (which is the red/blue designed for plants).

Byron.


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## Mikaila31 (Dec 18, 2008)

Byron said:


> I actually use a combo, but didn't want to confuse further since he already intends to retain one of the others. On my 115 it is a 6700K Life-Glo 2 and a 11000K Lightning Rod Super Daylight. On the 90g a Life-Glo 2 6700K and a ZooMed Coral Sun which is high in blue and from colour appearance must be around 10000K. On the 70g I have a Life-Glo 2 6700K and a Phillips Deluxe Daylight which is a cool white.
> 
> I remember your (Mikaila) mentioning elsewhere about using high-tech to propagate your plants to sell. You might want to consider a combo similar to what I've mentioned. In an article in the July 1987 issue of FAMA, K. Richards reported a study of various spectrums of light with the identical plants (Elodea) and conditions; plants grew strongest (producing more oxygen) under a combo of full spectrum and cool white; second under cool white alone; third under full spectrum alone; fourth under warm white alone. This study is cited in Diana Walstad's book Ecology of the Planted Aquarium, with the graph (p. 180). The plants produced 47ml of oxygen in each 24 hour period under the combo compared to 38ml under cool white, and 25 ml under Vita-Lite (which is the red/blue designed for plants).
> 
> Byron.


I can't use a combo unless they start making single combo lights like that similar to the 50/50 bulbs. These bulbs I really like and were recommended on a plant board. There is actually a sticky dedicated just to them. I do need new ones. Have never replaced my bulbs and I can tell they are starting to wear out. As far as their spectrum, the color spectrum for the bulb is actually on the box and they peak in red and blue with very little green peak. I use to use the "full spectrum" and still do on half of my tanks. Sometimes though it causes a very green look to the tank, like everything is washed over in green and I really didn't like that. I would prefer to use a combo of 6700K or 7000K along with these bulbs, but the 9325K only comes in T8s or 55 watt power compacts. My main tanks only run 1 or 2 bulbs and PC are not the same length of the tank, so one side would be one temp and the otherside would be the other temp. If plants grow best under a combo of full spectrum and cool blue wouldn't it just work best if you used a single bulb around 7500-8500K? I also thought that color temp alone only vaguely refers to the actual color spectrum of the bulb...

The bulbs I use have this reported spectrum on the packaging, as I said they are also reported to be 9325K. But it is not believed they truly are, estimated to be around 8000-9000K.


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## Byron (Mar 7, 2009)

I assume the study on best tubes only had those tubes to work with. I have noticed in the past 10 years a vast increase in the type of spectrum tubes compared to before, and the study was in 1987. Diana's point was that blue is important for aquatic plants, which makes sense since blue light penetrates water far better than red. And of course, we must remember that the majority of our aquarium plants are bog or marsh plants in nature, so water penetration is significant only during the submersed (flood) season. And that is when the plant is less active, not flowering, etc. Plus they occur largely in shaded areas, rarely in direct sun.

I've never noticed the green, but it may be the specific tubes I use. The Life-Glo 2, which to my mind has the best single-tube criteria, has this graph below. I combine this with a bluer tube.


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## Mikaila31 (Dec 18, 2008)

Interesting. I thought that when picking a bulb, at least on efficiency, when going by spectrum you wanted the largest peaks to be red and blue. Because basically isn't a color spectrum just telling you the general amount of light emitted at that particular wavelength? So wouldn't a bulb with higher red/blue peaks basically produce more usable light for the plants? I believe this is the basic reasoning behind PAR values... Thats why with the more expensive power compacts I searched for bulbs with high red/blue peaks and low peaks between 500-600nm. I've always thought this was important in picking a bulb, its actually the first think I like to look at if its available. I've always avoided bulbs that have a big green or yellow spike. I've always though it too be wasted light as far as plants go. Yellow can be used a little, but green is of really no use at all to a plant. Because of this it has bothered me that alot of plant bulbs have the biggest spike in the green/yellow wavelength.


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## Byron (Mar 7, 2009)

Yes, that was my thinking too. I've always been puzzled that with the spike in the green, the plants do so well, better than under the so-called plant lights with high red and blue and thus purplish hue. I can only assume the red and blue light in this tube must be high and sufficient.


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