# confused on power compact lighting



## observant_imp (Jun 30, 2004)

Hubby brought home an early b-day present for me--a 28 gallon bowfront with a CustomSeaLife power compact hood. The hood holds 2 65 watt bulbs plus moonlight. One is 10,000 and the other is actinic blue. 

The blue looks awful. And reading through the old threads I gather it's not a good bulb for a planted tank anyway. But reading through the posts has left me confused on what type of bulb I should replace it with. The box it came in refers to a amazon plant bulb which is a 5000, but reading the posts here it seems like I need a higher number--6500, 7200, etc from the posts I've seen.

If I'm going to keep the 10, 000 bulb, what is the best thing to have for the other? I've got a fluorite substrate and the rock has a strong orange hue to it. I'd like something that's good for the plants as well as pleasing to the eye. The actinic bulb really washes the color out of the tank.

Advice/education in this area would be appreciated.

Thanks.


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## ninoboy (Jan 26, 2004)

Mixing 10000K with 6700K makes a nice neutral color. But it's all depend on your personal preference.


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## ColinAnderson (Jun 25, 2004)

Most freshwater aquatic plants utilize light from within the 5000 - 7000 spectrum, making 6700k lights a good bet. 10000k is alright (you won't have to replace this one) as it has the appropriate spectrum and "more." I would say you could stick a 6700k bulb in there and be perfectly fine -- that should make a nice blend of lighing color as well.


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## trenac (Feb 15, 2004)

Most people use PC bulbs ranging from 5500K-10000K. The combo you use depends on the color that looks best for your tank. I personally like the 6500K.


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## observant_imp (Jun 30, 2004)

Thanks for the input. Sounds like 6700 is what I want.

I've been a Triton user forever--which means I've never had much more than 2 wpg. Do I have any suprises ahead with suddenly having the indulgence of 4 wpg?


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## trenac (Feb 15, 2004)

With that much light you will need to use C02 & ferts. I don't see any problems other than some algae. But once you get the hang of balancing nutrients, C02 etc. the algae won't be no problem. Just make sure to start out with a lot of fast growing plants to suck up the nutrients that the algae also grows on. Good luck :fish:


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## ninoboy (Jan 26, 2004)

Except the need of CO2 injection, nope. You just can see things clearer nowroud: 

Same like Trenac. I personally like 6500K or 8800K for non-mix bulbs fixtures. In the mixed bulbs, I use 6700 and 10000. For most people, maybe nobody even notice any difference between those bulbs. But I'm a bit picky and hate to see yellow or wash out blue.


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## Wasserpest (Jun 12, 2003)

Oh yeah! With that much light, you need a regular schedule of fertilizer dosing, CO2 injection, water changes, and lots of plants. Otherwise you will be growing algae... very fast!

BTW, plants don't utilize the 5000 to 7000 K spectrum. Spectral distribution can not be expressed in K. K (Kelvin) is some color temperature which does not tell you how good a bulb is for plants. That's been discussed to death... Color temps below 5000K will emit a "warm-white" yellowish light which, in connection with the green plants, looks awful to me, but it is personal pref.

You will find dedicated plant bulbs with 9325 or 18000K, and they are excellent for growing freshwater plants. You decide if the pinkish or bluish light is something you like or not. In the end, wattage is most important.


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## observant_imp (Jun 30, 2004)

Will one of the Hagen systems be adequate for a 28 gallon tank for co2?


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## Wasserpest (Jun 12, 2003)

With 130W of reflected PC light over it? No, I don't think so, not with the small yeast canister. 

It might work if you use two 2 or 3 liter soda bottles connected to the bubble ladder (or two of them).

Good luck! :fish:


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## ColinAnderson (Jun 25, 2004)

Wasserpest said:


> ... BTW, plants don't utilize the 5000 to 7000 K spectrum. Spectral distribution can not be expressed in K. K (Kelvin) is some color temperature which does not tell you how good a bulb is for plants. ... You will find dedicated plant bulbs with 9325 or 18000K, and they are excellent for growing freshwater plants. ...


So the 6700K is meaningless really? Sorry, I guess I don't fully understand the lighting situation then. :icon_redf I've always read that 6700K bulbs are great for growing freshwater plants. Are 9325 or 18000 better?


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## observant_imp (Jun 30, 2004)

Thanks for the input everyone. Looks like I'm about to start a whole new learning curve in terms of keeping this little tank balanced.


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## Wasserpest (Jun 12, 2003)

ColinAnderson said:


> I've always read that 6700K bulbs are great for growing freshwater plants. Are 9325 or 18000 better?


No... you simply can't use the color temperature to evaluate light bulbs on how good they are for plant growth. They are all really great bulbs. :wink:


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## aquabillpers (Nov 28, 2003)

Imp,

Your life would be a lot easier if you used just one of those 65 watt bulbs over your 28 gallon tank. You could get by with DIY CO2 (or none, maybe)and you'd need minimal fertilizing.

Good luck.

Bill


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## Urkevitz (Jan 12, 2004)

Imp if your LFS has Ge aquarays 9325k buy that bulb, IMO it looks better mixed with a 10000k than a 6700k.


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## Troy Hendrickson (Jul 18, 2004)

The color temp (K) of a bulb is basically nothing more than a means of rating the overall output. Heat a black oblect like carbon to 6700 degrees and the color it glows is the approximate color of a bulb rated at 6700K. If you've ever seen a piece of metal heated up in a forge, good comparison, it starts out red and gets whiter as it heats up.

But the color temp of a bulb doesn't really give you specifics of the spectral output of the bulb, specifically red and blue wavelengths which are the wave lengths plants use. It can however give you a rough idea, i.e. a 6700 bulb is probably going to be stronger in blue wavelengths than red, a 2700K bulb is probably going to be stronger in the red. The CRI (color rendering index) would be a better way of telling how smooth the overall output of the bulb is at glance, the higher the number the more accurately it's going to reproduce colors which would seem indicate at least a smoother output of all wavelengths, because peaks and dips in the spectrum would throw off color rendering accuracy.

Bulbs that have peaks in the reds and blues are good for plants, crappy for looking at them because the color rendering is skewed, so we pretty much go for for smoothness which generally means a higher color temp, 5000K or higher. But even 10,000K bulbs can have output in the reds and blues sufficient for plants and 5000K can to. At a ceratin point it amounts to personal taste in appearance.

Now then, someone will come along and shred this to pieces because this is the ultimate never ending debate. My personal preference is a 6500K bulb with a CRI of 85 or higher, and my tanks are showing very good growth with little algae concerns using them. But I have a friend who uses grolux bulbs and does just as well, it just looks funny to me.


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## Newticus (Jul 9, 2004)

I could be wrong but the colour of light isn't relational to output necessarily. 
The colour is measured by the temperature of the light in Kelvins. As well i don't think the number of the light is additive, eg, 10000K is 5000K + 5000K
(While arithmatically it is) 
the numbers are used as a qualitative description, not a quantitative one. So 2700 as physically in a different part of the spectrum then 8500. 
I'm not sure i'm explaining my self properly. 
so i will try again.
I always understood light waves to exist in a type of sequince. 2700 would occur before 6500 in the "line of colours" And so, while 2700 is before 6500, that doesn't mean that 6500 incorporates the colour wavelengths ahead of it

Now this is only how I understood light to work, i will gladly take any corrections

As an aside, and possible point of interest
The human eye is not the greatest judge of light colour (here comes the onslot) Our eye generally recognizes all lights the same. Now i do know that the light from an incandescent does look like a different colour than fluorescent (speaking in general, the way Fluorescents looked before options like daylight, soft yellow, ect). But compared to the actual difference in light temp, our eye barely recognizes it. If you've ever taken a photo with a non digital SLR without corrective film for your specific light you can see colour difference so much more. Halogens appear blue, fluorescents look green, and incandescent look yellow, generally.
I'm not looking for a debate in my aside and will not repsond to baiting. This is what i learned in photography class from a teacher who'd been in the buisness for years.


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## ninoboy (Jan 26, 2004)

Newticus,
Kelvin has nothing to do with color spectrum. As Troy explain, it's just a standard people use to determine a specific color to our eyes. They do it by heating a black carbon filament. So 5000K will be the color of that carbon at 5000K temperature. 10000K is the color of it at that temperature. 

I agree with you that people see color differently. I always see yellow on 6700K but my wife insists she sees green.


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## xjia (Mar 11, 2007)

Ok, just couple of questions:

1.If i want my plants look greener like this one you posted.
http://www.plantedtank.net/imageh/images/12/6032305a.jpg
What K(Kelvin) i need to get in order to get greener plants.

2.Which K(Kelvin)is best for growing plants,planted tank i mean regardless (co2,fertilizer etc....).

3.Does K(kelvin) helps much in plant grow or just for our eye sight pleasure?
4.Lower k(kelvin) <5000k means ill get a yellower/red tank and higher k(kelvin) >7000k means ill get a bluewish/purple tank colour ?

thanks in advance.


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## Overfloater (Jan 12, 2004)

Urkevitz said:


> Imp if your LFS has Ge aquarays 9325k buy that bulb, IMO it looks better mixed with a 10000k than a 6700k.


Good advice. I find 9325/10000 combo best to my eyes. It really brings out reds also.


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## BSS (Sep 24, 2004)

Welcome xjia!

Unfortunately, I'm not sure you'll get any good definitive answers to your questions. Your questions 3 & 4 seem to imply that you have a pretty good understanding that the K rating is really in a 'human visual' rating. To see which bulbs at similar K ratings would be best, you really need to see if you can get a light spectrum graph (or whatever they call it) of how much light the bulb produces across the entire light range. You want to look for bulbs with the biggest spikes in the red and blue ranges for the benefit of the plants. But, that bulb might not get you the best visual greens that you want to see. I looked for a number of the graphs a while back and didn't have much luck finding what I really wanted for most of the bulbs out there. So, I just opted for a bulb in the range I thought was best. I'd guess you'd want to target around the 6700K range.

Good luck!
Brian.


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## xjia (Mar 11, 2007)

ok,according to my understanding.

1.If i want to grow plant,i need to get light spectrum (nm) highest in red and blue regardless the K rating.

2.For greener plants,i need to get light spectrum higest in green(which dont help them in photosythesis).

3.If i want to statisfied my eye,i will probally need to get a bulb with higher K rating(towards blue/white), cuz lower K rating will bring yellow tint like water(i hate yellow colour water,thinks everybody too).

Conclusion: i'll get 2 bulb, for my 11g tank.15w each bulb 

1.Bulb with high red+blue spectrum(for plants) with high K rating 6700-10,000k(visual statisfaction).
2.Bulb high in green spectrum( for greener plant looking).(K rating 5000-7000 should be fine,does't matter)

correct me if im wrong, i will get a new bulb asap


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## spypet (Sep 15, 2006)

xjia said:


> Conclusion: i'll get 2 bulb, for my 11g tank.15w each bulb.


depending on what's available in your area, 
your conclusion should be in the range of;
6400-7200k yellow-white bulb-1
8800-10000k white-blue bulb-2
you do NOT want a 5000k bulb.


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## xjia (Mar 11, 2007)

Thanks for the quick answer,ill check the bulb tomorrow in my area.


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## snafu (Oct 9, 2004)

ninoboy said:


> Kelvin has nothing to do with color spectrum.


is this true? Planck's Law says that spectral radiance distribution is a function of blackbody temperature and frequency. 

i agree that you should look at the spectral response of the bulb (IF you can find it from the manufacturer), since the bulb ratings are only a coarse way of determining spectral radiance. they often accentuate certain frequencies depending on the particular application.


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## xjia (Mar 11, 2007)

i went to local shop today,and i get 3 brands of lighting:
my tank 11g.

1.Hagen-glo =http://www.hagen.com
2.sylvania =http://sylvania.aquanet.de/English/dframset.htm
3.Resun =http://www.resun-china.com 

15w,T-8
Hagen most costly,followed by sylvania and resun.
Hagen got life-glo , aqua-glo 18,000k cost ~$23, power-glo.
Resun got 10,000k but cost only $5 (can't find CRI for resun)

I need 2 bulb which one should i get first ?Need some idea from you guys.I plan to get
1.power-glo/life-glo
2.Resun 10,000k

any other combinations ?


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