Is a PL light necessary for a planted tank?
Is the normal FL that one can buy at most Luohan fish shop sufficient?
Anyone uses those lights from ikea?
How much would one 2 ft PL cost?
i'm using the lamps from IKEA, those screw on types with reflectors. it's equipped with dual sockets for normal E14 bulbs. changing to energy-saving bulbs soon. not recommended for plants cos its hot. and the light given out by the bulbs is a yellowish tone. i use them just to light up the tanks in my room.
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Its not the type of light tube/fixture that is impt. It is the quality and amount of light they produce.
PLs are popular because they take up less space on top of the aquarium for the same amount of light. Most times, you'll find it hard to fit enough FLs above a tank to get the prescribed 3watts/gallon of light for light demanding plants. If you're aiming for a low light tank, FLs will do.
Next is the colour of the light. Normally, planted tanks use lights that are rated between 6,000 to 7,000 kelvins... or most companies will just indicate "Daylight" on the packaging. These lights produce close to, if not white light, so the colours of your plants will look "correct" as far as human eyes are concerned. Next, these lights are full spectrum, offering a good spread of light colours for the plants to photosynthesise.
Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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A woman: without her, man is nothing.
Natural street freak
Most of what you call PL lights (Compact fluorescents) are not full spectrum but triphosphors.
There are a few full spectrum compact fluorescents but they are very, very rare and difficult to find.
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Resistance is futile, you will be administrated!
Opps... that shows my poor understanding of lights. []
Vincent - AQ is for everyone, but not for 'u' and 'mi'.
Why use punctuation? See what a difference it makes:A woman, without her man, is nothing.
A woman: without her, man is nothing.
Care to explain what you mean by triphosphors? Any adverse effect on the plant condition/health?
Natural street freak
No adverse effect using triphosphors (most people here use them). Triphosphors use a blend of phosphors that emit most of the light y three wavelenghts, blue, green and red (can´t remember the exact wavelenghts). Their light is very concentrated in those points. The spectral chart of this kind of fluorescents shows 3 big spikes in the blue, green and red zones. This way theese fluorescents emit more lumens and have a good colour rendition of 89.
Full spectrum or multiphosphor tubes use at least five phosphors to provide a more uniform distribution of light through all the visible spectrum. The spectrum resembles more closely that of the sun. This tubes put out less lumens because they spread all their energy throughout the whole visible spectrum. But they have a very good colour rendition of 95 or more.
Although you probably think full spectrum fluos are better this does not seem to be correct, most people here use triphosphors and you can keep difficult and demanding plants. Triphosphors are used quite often among Dutch aquarists too, although they seem to prefer yellower colour temperatures.
PAZ.
I have a set of PL lights and 2 sets of FL lights (4ft). For FL, I use Phillips 865 ($2.90 per pce) which has >85 Ra and produce about 3100 lums. I have good results so far. I was looking Phillips 965 from the same source which has Ra of >95 but they do not carry due to low demand and perhaps also expensive. I wish to give it a try, do anyone knows where I can get it?
FC,
Care to share what is the difference 865 and 965? I'm guessing the difference is the colour rendition but how would it affect the plants?
OK one thing worth noting is that lights with a high CRI... say RA>90, typically have lower light output. As an example, the philips 965 light output is about 1000 lm lower than the 865 (If I remember right). This general rule applies to most brands which I looked at when I was reading up on FL/PL tubes.
As for full spectrum and tri-phosphors and full spectrum tubes, take a look at this thread. If you look at the spectral curves, you can see quite clearly which are tri-phosphors and which are full spectrum (Osram biolux, and the bioplast tube). If any of you would like to try a full spectrum tube, you can try the biolux tube... I used to have the distributor contact somewhere. I'll see if I can dig it up. There are also a couple of reviews on the biolux tubes on the krib. Of course you could try the bioplast tube, but it will be costly.
Allen
IMO, Colour Representation Index (Ra) has no significance in the evaluation of light source for plants.
Ra is just a index of perceived colour illuminated by a light source of a colour temperature compared to the perceived colour illuminated by a black body heated to the same colour temperature.
A incadescent bulb has Ra close to 100. But it is no good for use in planted aquarium.
BC
On the other hand, lumens measure the flux engergy perceived by the visual sensibility(380nm to 780nm). The visual sensibility range does not correspond to that of the range plants use for photosynthesis. Therefore, lumens do not tell the full story too.
BC
I agree... current wisdom now emphasizes intensity rather than spectrum. Which may mean that tri-phosphors may actually perform better as compared to full spectrums with lower light outputs.
For myself, I've actually got a stock of 6 full spectrum tubes which I'm waiting to swop in the next time I change my tubes. Hoping to see for myself if the tank performs better or worse than before.
Allen
Again thats true... If we really want to see the true story, we should look at the PAR rating of the tube. Unfortunately, this is almost never given. As such, we often have to settle for the Lighting Intensity (in lumens), which is close, but as you mentioned, does not tell the full story.----------------
On 2/24/2003 3:53:22 PM
On the other hand, lumens measure the flux engergy perceived by the visual sensibility(380nm to 780nm). The visual sensibility range does not correspond to that of the range plants use for photosynthesis. Therefore, lumens do not tell the full story too.
----------------
Allen
"As an example, the philips 965 light output is about 1000 lm lower than the 865 (If I remember right)."
If you are refering to 4ft tube, I think it is not that drastic. I think it is about 2500 lms (965) vs 3100lms (865). Both are so called full spectrum lamps with 965 being higher in colour quality.
If I am correct, lumens are measured at the spectrum range that is catered for human's eyes.
I wish to try 965 for its' RA performance to see if that makes any diff. I think RA is the comaprison of how close an artificial light source is to the sun light.
FC,
if you need try looking for the OSRAM Biolux tubes... I think they are Ra 97.
Allen
Since lumens is the measure of lights, shouldn't we be choose based on this?
IMO, as long as the colour temp falls between 6000K~7000K The higher lumens would be the best choice for aquarium lighting. Correct me if I'm wrong.
Hehe Sherwin... here comes the correction...Lumens is a measure of light intensity as perceived by the human eye. Now consider this... the eye is sensitive to greens, while plants being mainly green, often do not use the green spectrum effectively.
Consider the following diagram...
Note that the photosynthetic activity in the green spectrum is low. So in short, a measure of light intensity which is biased towards the green spectrum, cannot be considered accurate when considering plants which prefer light in the red and blue spectrums. Thats why people have come up with PAR which is a measure of light intensity according to plant requirements.
Allen
Natural street freak
Lumens mean little to plants, for instance, low pressure sodium lamps produce more lumen per watt than any other artificial light source but they are useless for growing plants, they put most of their radiant energy in the peak of human light sensitivity.
So I get it now... PAR would be the measurement of energy for photosynthesis.
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