# Mixing the spectrums



## essabee (Oct 11, 2006)

Some of you know that I am building a new aquarium for myself, its about 1000 liters and will have plants and pressurised CO2. The water depth shall be about 2 feet.

I have already ordered the lights for the aquarium. Its going to have 5 nos. Metal Halide 150 Watts fixtures and also 4 nos. 36 Watts PLL fluorescent. The tank shall also receive some direct and indirect sunlight from the terrace side where I have a tinted glass hatch opening in the canopy of the tank.

I have always believed that a full spectrum is the best light for an an aquarium - planted or otherwise. A full spectrum will bring out the true colours of whatever the tank contains. When it comes to planted aquarium the spectrum and the intensity of light becomes even more interesting. Now its my hypothesis that if plants are given a flat intense spectrum of all the colour bands used for photosynthesis - each specie of plant will develop its full colouration and you will also be able to see it in all its glory.

The limitation are the bulbs available to us. Each bulb has its limitation in reproduction of the visible spectrum. So I have decided to solve the problem by mixing the spectrum. Past year I started mixing florescent bulbs with different spectrum in my smaller tanks with some success. Then you all know that florescent bulbs are not full spectrum ever and limited to the colours emitted by the specific phosphors in the mix of the coating.

My new tank provides me the opportunity of mixing the spectrum of MH bulbs. Out of the 5 nos. 150 watt bulbs 2 shall be of 10000K and three of 3000K. The 4 36W florescent shall be of 6500K. I expect the final light to look a little yellower than the 6500K MH. Somewhat like golden sunlight.


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## Damonc1964 (Aug 23, 2009)

essabee,

I'm new to the hobby and am looking for some advise. I like your logic and I'm very interested in achieving the same thing in my standard 55 gallon tank. I'm currently low in wattage and need to add more lighting. All I have right now is a power compact fixture with two 65 watt, 10,000k actinic combo bulbs. What kind of lighting would you recommend to supplement what I have?

Thanks,
Damon


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## essabee (Oct 11, 2006)

It has been consistently observed that spectrum with an intensive blue end causes more foliage growth and an intensive red end causes strong stems and roots. So you need lights where both ends of the spectrum is strong but don't forget the midrange that is what we see better.

Your intent will guide your deployment, Damon. To use more than 2 watts per gallon will require CO2 enrichment to avoid algae issues. So do not venture above 110 watts of total lights using normal (not HO) florescent T5. I would recommend 3 Philip 36 Watt PLL using 1 warm daylight (2700K) and 2 cool daylight (6500K) or their equivalents. 

I like total enclosing hoods for my aquariums with all the sides reflective. I like multi sources of lights and avoid those parabolic reflectors. If you do not allow light to escape - you will not loose any light efficacy below the albedo of the reflective surface. More - having your bulbs giving off light in this fashion will keep the umbra shadow very small and the leaves of your plants will not shade out the one behind it totally.


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## Damonc1964 (Aug 23, 2009)

essabee,

Thank you for sharing your knowledge.

I have Co2 injection through a DIY system which I can easily maintain 30ppm so I will take your advice and buy the new lighting.

This much lighting will not be harmful to my fish will it?

Here is a pic of my tank and fish.


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## Makoto (Nov 6, 2008)

I heard GE 9k mixed with 6k is good combination, if you're buying CF stick with the 55w cause the 65w tend to burn out quicker and becomes dull in short time span.


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## essabee (Oct 11, 2006)

I had recieved on Friday evening the bulbs I had ordered. I made some changes in the current 1000L tank - The Incomparable. Out of the 5 150W - MH 3 are now 10000K and 2 are 3000K. Keeping the 5 40W T8 2700K off the tank looks much brighter and the colour looks so natural that unless you open the top and make sure, you would think it is an outdoor tank lighted by natural light. Oh! I just love this combination. 

I believe the brightness increased because the intensity of the green-yellow in the resultant spectrum has increased. That's not all, the pink granite that I had used to build the rear and the side walls now looks pink, a colour I could only see when there was direct sunlight in the tank. 

I do not want to reduce the wattage of the lights used for this tank or I would be changing the experiment I have taken up. If I light up the 2700K T8 then they will make the present resultant spectrum lopsidedly high in the yellow bands. The type of T8 I now need is something like the Azoo Tri-Power which spikes at the red and blue ends. I think those will be just right. I hope I can find 5 X 48" of those.


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## Crispino Ramos (Mar 21, 2008)

I like 3/4 daylight and 1/4 blue light for bringing the red and green colors on plants (it's also pleasant on the eyes).


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