# Do I really need 6700K lights?



## ianiwane (Sep 7, 2004)

So you plan on using just the 10000k bulbs right? If you are not going to use two of the outlets and just use the 10000k that is fine. There is no need to switch the 10000k to 6700k. They will both grow plants fine. Actinics on the other hand will not.


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## crazie.eddie (May 31, 2004)

Correct, I do plan to use the 10000k bulbs only. I'm going towards a low light planted tank solution for now. I understand that I'll have high lighted areas and dark corner areas with my current lighting system, especially just using the (2) 96 watt bulbs. I'll just make sure to avoid planting in the dark areas.

Thanks for the info.


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## jhj (Jan 31, 2006)

crazie.eddie said:


> From what I understand, the main difference is just from our eyes since the 6700K produces more yellow and 10000K lights more blue, which the plants don't really care about.


Main difference is not to the eyes, but to the plants. The plants thrive in the 5000-6700k spectrum. They will be alright in the 10,000k spectrum, but the useful light (to the plants) would be less


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## darkfury18 (Apr 1, 2006)

jhj said:


> Main difference is not to the eyes, but to the plants. The plants thrive in the 5000-6700k spectrum. They will be alright in the 10,000k spectrum, but the useful light (to the plants) would be less


the color temperature is the color that our eyes see. how effective the bulb will be depends on the spectrum that it produces not the color temperature. in general any full spectrum bulbs will suffice.


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## Reefcrack (Oct 19, 2005)

*Just have enough watts per gallon*



crazie.eddie said:


> So could someone please enlighten me?


Funny, i get jokes! 

I would just make sure you have sufficient wattage for the tank size. I know you wanted to go low tech, but I would imagine you still need a minimum wattage/gallon.

Jim


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## crazie.eddie (May 31, 2004)

LOL. You were the only one that caught that.


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## ianiwane (Sep 7, 2004)

jhj said:


> Main difference is not to the eyes, but to the plants. The plants thrive in the 5000-6700k spectrum. They will be alright in the 10,000k spectrum, but the useful light (to the plants) would be less


Not true, plants will use the 10,000k light just fine. In general the 10,000k bulbs produce a whiter crisper light than the 6,700k bulbs. Its all about personal preference. I use 8,800k, 10,000k, 6,500k, and 12,000k right now and don't see a big difference. I have used 6,700k bulbs in the past and the bulbs I am using right now work just as well.

Ian


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## Daniel*Swords (May 8, 2006)

Here's a photo comparison between different bulbs made by a Finnish aquarist.
It does have some minor problems as noted by the photographer... esp. with the white balance being fixed for all.

I thought that this might be a nice reference for you guys too when choosing the bulbs!


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## csf (Jul 10, 2003)

You can grow plants in the 3500 and 2700k bulbs from Home Depot. The important part is if you like looking at your tank.


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## medicineman (Sep 28, 2005)

Throw all the kelvin based thought to the trash when thinking of choosing what kind of bulb to grow plants. The Kelvin usually indicate the general combined output out of a lamp and does not dictate strictly. Of course it is still can be used to predict what kind of colour it will appear as (to decide what you like).

The issue here is light wavelength, or should I say spectrum output to make it simple. Plants are much more sensitive to red (600-680 nm) and blue spectrum (380-480 nm) when it comes to photosynthesis. This is proved scientifically for a long, long time and that is how manufacturers can make expensive special bulbs for plants which are very rich in red and blue spectrum.


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## Ktulu_JL (Apr 3, 2006)

I agree with medicineman 100%.

When I set up my last tank, a 29 gal, I used 3 2xODNO T8 bulbs that consists of: a ZooMed FloraSun "grow bulb" that concentrated on the red part of the spectrum, a generic home depot "~5000K" bulb as intensity filler, and a ZooMed OceanSun 10,000K bulb to normalize the light color in the tank. I don't see any kind of massive growth difference on stem plants in this tank versus the generic 6500K bulbs that are sold everywhere that I have been using in the past in other tanks.

From my experience, and I am sure I might be wrong, 6000-7000k bulbs look good in planted tanks, and anything lower will need to be offset by the 10,000K'ish bulbs to make your fish an plants look nice. Plus when your fish go under the different bulbs, they will look better or worse... so it is up to you.

I say ditch the actinics and get some 6000K range more or less and you "should" be happy....


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## Fishstein (Jun 5, 2006)

Hi Crazie Eddie,
Please check out my thread - Best T8 48 in. bulbs for plant growth + "whitening" my greenish full spectrum bulbs - I just completed a ton of research on this and I think you'll find it very helpful. I have been using Verilux T8 6280 94.5 CRI full spectrum bulbs up to now that I got wholesale - and they've been ok - but I found a way to improve on these both for look (visible light) and plant growth.
Best,
Fishstein


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## Fishstein (Jun 5, 2006)

Also, you can now get high quality full spectrum 6500K 85 CRI bulbs from Home Depot for $4. I think they're called Daylight Deluxe.


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## SuRje1976 (Feb 2, 2006)

crazie.eddie said:


> I'm planning to go the low tech route, but my Coralife 72" lights came with (2) 96 watt 10000K lights...


What size is the tank? That's a lot of light!


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## crazie.eddie (May 31, 2004)

SuRje1976 said:


> What size is the tank? That's a lot of light!



Not really. It's a 125 gallon tank. I'm only running about 1.5 wpg, since I'm only using (2) 96 watt lights, . If I changed the actinic to 6700K bulbs, then I'ld be at 3 wpg, running (4) 96 watt lights.


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