# How many k?



## cbachmann (Aug 6, 2013)

I'm in the midst of setting up a 5.5 gallon tank low-tech (no CO2, ferts) planted tank as inexpensively as possible. I'd like to use a regular bulb in a normal desklamp type fixture, but I was wondering if the k range matters. Right now I have an awesome LED bulb rated for 3000k and 13w, though the package claims that it replaces and 80w bulb in terms of brightness. I really like this setup because it has literally zero heat and I'm not worried about it shorting out so close to the water. Should I look around for a different LED bulb or maybe switch to a CFL bulb? Does the k rating actually matter for plant growth?


----------



## OVT (Nov 29, 2011)

The "K" is mostly how plants look to you.
The "spectrum" is how much of different light wavelengths (red, blue, etc) is visible to plants.
The PAR is roughly how much energy the plants get.

The last two is what really important to plants.

I say if you like your current LED bulb, then keep it.
If overtime the plants start not looking that great to you, then post pictures and go from there.

v3


----------



## aznartist34 (Nov 19, 2010)

The k range is kelvin temperature scale. That measures the colors perceived by the human eye. As OVT posted above, you want to look at the spectrum of wave lengths (colors) that are beneficial to plant growth. Generally the spectrum of lights ranging from 5000k to 7000k are suitable for plant growth but the actual spectrum of the light is typically hard to find since the manufacturers don't have it listed. Easy route would be to get a small 10w spiral cfl bulb around the 6500k range.


----------



## AutumnSky (May 19, 2012)

I got mine at Ace - mine is the 
Ace brand but here is a GE one 6500K or 6700K 
http://www.acehardware.com/product/index.jsp?productId=2903524

I had a hard time finding these, around here they tend to be in the 2700-3200 K appx for daylight.


----------



## jeffkrol (Jun 5, 2013)

AutumnSky said:


> I got mine at Ace - mine is the
> Ace brand but here is a GE one 6500K or 6700K
> http://www.acehardware.com/product/index.jsp?productId=2903524
> 
> I had a hard time finding these, around here they tend to be in the 2700-3200 K appx for daylight.


Technically they are approximating incandescent light bulbs at that temp (3000k-ish).. "Daylight" is 6500K.


----------



## jeffkrol (Jun 5, 2013)

cbachmann said:


> I'm in the midst of setting up a 5.5 gallon tank low-tech (no CO2, ferts) planted tank as inexpensively as possible. I'd like to use a regular bulb in a normal desklamp type fixture, but I was wondering if the k range matters. Right now I have an awesome LED bulb rated for 3000k and 13w, though the package claims that it replaces and 80w bulb in terms of brightness. I really like this setup because it has literally zero heat and I'm not worried about it shorting out so close to the water. Should I look around for a different LED bulb or maybe switch to a CFL bulb? Does the k rating actually matter for plant growth?


In a sense K does matter in the fact that not all of the light spectrum is optimal for plant growth.. AS a reference point on 6000k vs 3000k (not all 3000k are equal either): 








http://www.gl-leds.com/led-bulbs/e27-led-bulb-light.html

One has more photosynthetically active blue, the other red.. sort of balances.. "White" Leds are generally blue LED's w/ phosphors added... so it becomes more difficult to generalize since all companies "magic sauce" differs 

As to aesthetics, I personally find 3000k too yellow for my taste..preferring a crisper white. After looking at the above spectra my choice would be... both (though not that style of bulb BTW)..


----------



## roadmaster (Nov 5, 2009)

I like the look I see, from 10,000K/6700K combination.
Plant's seem to like it also.


----------



## AutumnSky (May 19, 2012)

jeffkrol said:


> Technically they are approximating incandescent light bulbs at that temp (3000k-ish).. "Daylight" is 6500K.


No argument for what it is supposed to be, though the majority of bulbs even that say daylight are in the 3000K range - every grocery store I looked in, and even Lowes and HD here in Colo. Walmart too. :icon_lol:

I didn't almost ever go to ACE, so happy to have found the bulbs. I was looking for almost a year! Now they are supplemental for my planted bowl and little tidbit (plant scraps) bowl/vase.

Walmart even had a planted tank bulb in the 6700K I think (ZooMed and I think I have seen Aqueon too). I think I also saw them in Petco and Petsmart, if you are trying to keep it with no shipping expense. I am still learning. :icon_wink 

For most people who don't need special lighting to keep up with cO2, or very high light plants, these are great for a basic set up.


----------



## AutumnSky (May 19, 2012)

roadmaster said:


> I like the look I see, from 10,000K/6700K combination.
> Plant's seem to like it also.


I had that light combo on my JEBO tank. It looked nice. I had a beautiful jungle with some good Ferka ferts!


----------



## Edub (Mar 23, 2011)

roadmaster said:


> I like the look I see, from 10,000K/6700K combination.
> Plant's seem to like it also.


 
This is the exact color combo I like. Its bright white without being too "blue" and the reds really stand out. Plus, I have noticed the plants LOVE it. I have run with just 6700k and I think its a bit too yellow, anything less than 6700k is WAY too yellow for me without some other bulb to balance it out.


----------

