# 4100K florescent



## balutpenoy2oy (Feb 17, 2011)

HAPPY NEW YEAR ,,, Hi guys is 4100K HO T5 light will do good in planted tank ? HD selling it for under $10 per tube ..


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## pyrrolin (Jan 11, 2012)

Personally I wouldnt use 4100 k


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## balutpenoy2oy (Feb 17, 2011)

pyrrolin said:


> Personally I wouldnt use 4100 k


Any reason why.


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## Darkblade48 (Jan 28, 2008)

It is too yellow for my taste.

You may want to try 6500K which is a little whiter/tinted blue.


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## pyrrolin (Jan 11, 2012)

the colour would not look good to me, I like around 6500 k for daylight type look


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## fishclubgirl (Mar 4, 2010)

Freshwater plants do better with 6700k and it's actually more of a bluer light and is comparable to a cool white. I just switched a bunch of cfls to cool white and my plants are taking off!!


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## pyrrolin (Jan 11, 2012)

6500 or 6700, all depends on the manufacturer, at petsmart the bulbs are 6700, at another local store they have zoo med bulbs and they are 6500.

Both are basically the same and I bet 99 percent of people couldn't tell the difference.


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## BillD (Jun 5, 2006)

I'm guessing HD doesn't have a 5000K or 6500K tube in T5, at this time. My preference is for 5000K, but 6500K works also. Aside from the fact the 4100k isn't great for growing plants, you probably won't like the way it looks, because it looks much like incandescent "Soft White", which is kind of yellowish, as mentioned.


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## balutpenoy2oy (Feb 17, 2011)

So it is better to leaned on the bluer side of spectrum ( daylight has blue hue on it ). How about the 10000K ? If this is too much , what possible Kelvin temperature should I combine to it or this is not possible ? I am already running this light combination ( 10000K & 41000K ) on my 75G for 9 hrs photo period and a week already. My light fixture has two sets of this. The set-ups are 1000K,4100K,10000K and 4100K respectively they are all 54 watts each and HO T5. First 10000K and the last 4100K is a set that I am using, middle set is always off. My friend has a really blue light ( actenic he said ) and it will be free for me, can I use this on my planted tank ? 
Oh my ! i am asking to much. Anyway many questions = many input


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## DaFishMan (Dec 19, 2006)

I mix 6700k and 10000k. That being said as Bill said 5000k will grow plant. Any less than that isn't worth it.


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## Darkblade48 (Jan 28, 2008)

Actinic lighting will not be useful for plants.


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## pyrrolin (Jan 11, 2012)

I had atinic lighting for a week or so and my algae grew totally nuts


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## balutpenoy2oy (Feb 17, 2011)

Thanks guys..


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## SmokeSR (Jan 28, 2009)

If you want cheaper bulbs, check homehardware and homedepot's website. They often don't stock non-common sizes and colours but they are able to order them in. Homehardware ordered me in 18" T8 in 6500k for $6.49 each.


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## Fishfur (Mar 4, 2012)

If you google plants and light, you'll find a ton of information, probably far more than you ever wanted to know, about the colour spectrums and intensities of light most useful for growing plants. Generally speaking, the closer it is to the natural spectra of daylight, the better it will grow plants, in or out of water.

Standard Cool White bulbs are what I used to use in my light garden, because the 'plant bulbs' at the time time were so costly. They did pretty well, but some of my succulents would get leggy. You can still get 'plant bulbs', but they cost more and are not better, in some cases they're not very useful at all. One I checked into was, iirc, less than 4000K. They put colour coatings on them to influence the colour spectrum they put out, because some colours are more useful to plants than others. Blue is one of those.

Now I use 65 or 6700 K T12s, mostly, I think one pair are T8s. I have, trying to remember without going to look, either ten or twelve of them close together over the garden and this setup grows every succulent I could ask for, and all the ones I used to have a hard time with. But they are also very close to the plants.. in some cases they're touching part of the plants, and that makes a big difference too.

You can't get lights that close to plants in an aquarium, so intensity becomes a greater issue with the depth of the water the plants are in. Water diffuses and, I think the word is difracts, ?, light, so the deeper you go, the less light there is and the colour changes too. Deep water, like lakes or seas, the light looks blue, because the reds and other colours don't penetrate as far. You also have to consider anything you might have floating that would physically block light.

Try checking the term PAR.. photosynthetically active radiation. It means the light that is actually useful to help plants perform photosynthesis, or make food. The meters to measure this are not cheap, so most of us don't have one, but I think it's useful to at least have an idea why some lights are better than others, and which ones are most likely to get you the results you want at the least cost. Currently I use 23 W spiral flourescents that are rated for 6500 K.. and get pretty good results from them. They won't grow the very demanding high light plants, but they will grow almost anything else. Tubes would be better, but for now, these are cheap and mostly provide what I need.


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## balutpenoy2oy (Feb 17, 2011)

@ Fishfur "Standard Cool White bulbs are what I used to use in my light garden, because the 'plant bulbs' at the time time were so costly. They did pretty well, but some of my succulents would get leggy. You can still get 'plant bulbs', but they cost more and are not better, in some cases they're not very useful at all. One I checked into was, iirc, less than 4000K. They put colour coatings on them to influence the colour spectrum they put out, because some colours are more useful to plants than others. Blue is one of those.

I am kind of wondering actinic is blue and yet this is not good to plant , i am searching for the reason why but get non. And 3500K is much better than 4100K because former is leaning on the red side of spectrum ? HD is selling 3500K T5 48" CRI 85 in lesser wattage I remember its 26W only is this good ?


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## Fishfur (Mar 4, 2012)

The actinic lights are meant for salt water tanks only, for corals, I believe. They don't have enough of all the spectra that plants can use.. that's why they are not useful for plants. They've been made to mimic the specific blue light salt water life gets where it grows. And while generally, higher K temperature lights work best, you want those that mimic daylight reasonably well, which are the ones from 5000 to 6700 range. These will also penetrate a bit farther into water, thus making them more useful for aquarium plants. See the section below on the inverse square law. I'm no mathematician, but simple observation will show it to be true.

Have you ever seen a plant showing signs of etiolation.. aka, getting leggy, or 'stretching for the light' ? The nodes get farther and farther apart, stems get thinner and thinner, leaves get smaller and smaller, and it's all caused by lack of enough light. I'm not addressing nutrient needs here, just light. Actual daylight always produces the best growth results, whether it is full sun or shade does not matter so much. If you grow some indoor plants, they will always look different if grown outside for the summer. I think this is simply because daylight is what they evolved to use, but it's also because outdoor light intensity is higher than it is indoors and contains all the spectra, including those we can't see, such as UV. Indoor light is always less intense, unless you make efforts to increase it, by using lights made to mimic daylight.. but all they do is mimic it, they can't quite replicate it exactly. For example.. I had frogbit plants I kept outside last summer and one bloomed.. that virtually never happens indoors. The reason it flowered is most likely because it was getting sunlight, not artificial light.

Also consider how different daylight can be in different parts of the world.. tropical belt sun is much stronger, more intense, than what we get here in Canada, even in summer. And while blue light is believed to enhance vegetative growth, it can't make a plant grow well if that's the only colour, or almost the only colour, that it gets. A balance of some sort is needed, because in nature plants get all the light spectra, not just what we think they need. The following may help explain a couple of points better.

Excerpt from article on Wikipedia.

Quote " Grow lights are used for horticulture, indoor gardening, plant propagation and food production, including indoor hydroponics and aquatic plants. Although most grow lights are used on an industrial level, they can also be used in households.

According to the inverse-square law, the intensity of light radiating from a point source (in this case a bulb) that reaches a surface is inversely proportional to the square of the surface's distance from the source (if an object is twice as far away, it receives only a quarter the light) which is a serious hurdle for indoor growers, and many techniques are employed to use light as efficiently as possible. Reflectors are thus often used in the lights to maximize light efficiency. Plants or lights are moved as close together as possible so that they receive equal lighting and that all light coming from the lights falls on the plants rather than on the surrounding area.

A range of bulb types can be used as grow lights, such as incandescents, fluorescent lights, high-intensity discharge lamps, and LEDs. Today, the most widely used lights for professional use are HIDs and fluorescents. Indoor flower and vegetable growers typically use high pressure sodium (HPS/SON) and metal halide (MH) HID lights, but fluorescents are replacing metal halides due to their efficiency and economy.

Metal halide lights are sometimes used for the first (or vegetative) phase of growth as they have some blue light; however, they have peak intensity around yellow spectrum.

Blue spectrum light may trigger a greater vegetative response in plants.[citation needed]

High pressure sodium lights are used for the second (or reproductive) phase of growth as they have a reddish light.

Red spectrum light may trigger a greater flowering response in plants. If high pressure sodium lights are used for the vegetative phase, plants grow slightly more quickly, but will have longer internodes, and may be longer overall.

Also, MH bulbs with added reddish spectrum and HPS bulbs with added bluish spectrum are also available for fuller spectrum and added flexibility during both vegetative and flowering phases.

In recent years LED Technology has been introduced into the grow light market. By designing an indoor grow light using diodes, the exact wavelengths necessary for photosynthesis are used to create LED grow lights that are used for both the first (or vegetative) phase and the second (or reproductive) phase of growth. NASA has tested LED grow lights for their high efficiency in growing food in space for extraterrestrial colonization.

Light spectra used

Natural daylight has a high color temperature (approx. 5000 K). Visible light color varies according to the weather, and angle of the Sun, and specific quantities (measured in Lumens) of light stimulate photosynthesis. Distance from the sun has little effect on seasonal changes in the quality and quantity of light and the resulting plant behavior during those seasons. The Earth tilts on its axis as it revolves around the sun. During the summer we get nearly direct sunlight and during the winter we get sunlight at a 23.44 degree angle to the equator.[citation needed] This small tilt of the Earth's axis changes the effective thickness of the atmosphere with respect to the distance sunlight has to travel to reach our particular area on Earth. The color spectrum of light that the sun sends us does not change, only the quantity [more during the summer and less on winter] and quality of overall light reaching us. The color rendering index allows comparison of how closely the light matches the natural color of regular sunlight.

The light spectra of different grow lights

Different stages of plant growth require different spectra. The initial vegetative stage requires blue spectrum of light, whereas the later "flowering" stage is usually done with red-orange spectra.
Unquote "


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## fishclubgirl (Mar 4, 2010)

One other thing to note is how clean the top of your tank is. If your tank lid is dirty or your tank is covered in floating plants, lights are going to be less effective. Amazing how many aquarists don't note this, including myself


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## Fishfur (Mar 4, 2012)

Very true. Floating plants block quite a bit of light, and if you have, say, a layer of duckweed, it would cut the light dramatically.


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## balutpenoy2oy (Feb 17, 2011)

Fishfur said:


> The actinic lights are meant for salt water tanks only, for corals, I believe. They don't have enough of all the spectra that plants can use.. that's why they are not useful for plants. They've been made to mimic the specific blue light salt water life gets where it grows. And while generally, higher K temperature lights work best, you want those that mimic daylight reasonably well, which are the ones from 5000 to 6700 range. These will also penetrate a bit farther into water, thus making them more useful for aquarium plants. See the section below on the inverse square law. I'm no mathematician, but simple observation will show it to be true.
> 
> Have you ever seen a plant showing signs of etiolation.. aka, getting leggy, or 'stretching for the light' ? The nodes get farther and farther apart, stems get thinner and thinner, leaves get smaller and smaller, and it's all caused by lack of enough light. I'm not addressing nutrient needs here, just light. Actual daylight always produces the best growth results, whether it is full sun or shade does not matter so much. If you grow some indoor plants, they will always look different if grown outside for the summer. I think this is simply because daylight is what they evolved to use, but it's also because outdoor light intensity is higher than it is indoors and contains all the spectra, including those we can't see, such as UV. Indoor light is always less intense, unless you make efforts to increase it, by using lights made to mimic daylight.. but all they do is mimic it, they can't quite replicate it exactly. For example.. I had frogbit plants I kept outside last summer and one bloomed.. that virtually never happens indoors. The reason it flowered is most likely because it was getting sunlight, not artificial light.
> 
> ...


Every informative ....Thanks


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## balutpenoy2oy (Feb 17, 2011)

fishclubgirl said:


> One other thing to note is how clean the top of your tank is. If your tank lid is dirty or your tank is covered in floating plants, lights are going to be less effective. Amazing how many aquarists don't note this, including myself


Even the florescent tube needs to be cleaned, accumulation of dust makes it dimmer...


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