# Please look -  good for plants ?



## arty (22 Jun 2010)

Please look at this link: http://www.lampspecs.co.uk/Light-Bulbs- ... va-54-Watt

Narva Bio Vital 1149mm T5 Fluorescent Tube 54W

# 54 Watt 958 Bio Vital 5800K
# Colour rendering over 90% accurate
# Full spectrum including UV supports S.A.D. treatment
# For applications that require natural colour rendering

Good for plants or UV can cause some damage ?


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## ceg4048 (22 Jun 2010)

Hi,
 Can't see anything wrong with those bulbs. None of those parameters listed have any relevance to plant growth so no worries there.

Cheers,


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## mdhardy01 (22 Jun 2010)

And with the uv you can get a tan at the same time as watching your fish!!!!


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## arty (23 Jun 2010)




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## dw1305 (23 Jun 2010)

Hi all,
Arty unless you particularly like the colour rendering of the "Bio Vital" tube in the link, there are other suitable tubes cheaper. http://www.lampspecs.co.uk/Light-Bulbs-Tubes/860-and-865-Daylight_14.

The  T5 Fluorescent Tube 54W "865 Sylvania" is Â£2.45 + VAT.

cheers Darrel


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## arty (23 Jun 2010)

Thanks for advice. 
What do You think which better with same price but different Lumens and lifetime ?

Sylvania Luxline 54W

# Triphosphor 865 6500K Daylight
# Colour rendering 85% accurate
# 16mm Diameter 54 Watt High Output FHO
# 20,000 Hours Life
Lumens 	4050

Or

GE Starcoat T5 Long Last 1149mm Fluorescent Tube 54W

# Triphosphor 865 6500K Daylight
# Colour rendering 85% accurate
# 16mm Diameter 54 Watt High Output HO
# 30000 Hours Life

Lumens 	4750


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## dw1305 (23 Jun 2010)

Hi all,
It is just down to the look you like. Have a look here for some more information:
<http://www.theplantedtank.co.uk/lighting.htm> and James sticky thread in this forum,
<http://ukaps.org/forum/viewtopic.php?f=50&t=555>

cheers Darrel


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## ceg4048 (23 Jun 2010)

Lumens are a completely irrelevant parameter within the context of plant physiology and growth. Instead, as mentioned above, you should focus more on the aesthetic appeal of the colours of the bulbs you are interested in. There will be no difference in performance between any of these bulbs unless the PAR values differ. Since there is no correlation between PAR and Lumens you cannot use this rating to predict performance. Lumens are a measure of how humans perceive light. It is not a measure of how plants use light. Therefore it is basically a useless parameter. That is why we have the sticky => Cheap HO T5 fluorescent tubes - Update with photos 

Cheers,


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## arty (23 Jun 2010)

Maybe I'm wrong. But i think Lumens are the same light intensity concentrated into an area, higher lumens higher intensity of light - right or not ? As comparison with lower lumens light can keep more close to water with same efect and with higher lumens higher.
Lower twice intensity and plants get twice less acceleration in growth. I understund without right color rendering can't grow, but without light intesity too.
When i adjust my luminaire higher - intensity lower and  plants don't pearling as before.
In our situation lighting area concentrated in to fish tank.
As sample Metal halide can too same parameters but very large amount of Lumens what's is dangerous if close to plants, need keep at least 1m above tank then light spread on more large area and intensity lower.
And if deep fish tank i think Lumens play role.

Please look from Wikipedia:
"The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux. Mathematically, 1 lx = 1 lm/m2.

A single fluorescent light fixture that produces a luminous flux of 12000 lumens might light a residential kitchen with an illuminance of 500 lux. Lighting a larger area to the same illuminance requires a proportionately greater number of lumens."

Also here from net some words about PAR - Lumens per watt :

"PAR is probably one of the most important considerations along with the related Useful Light Energy, Lumens per Watt, Focused Lumens and Watts per Gallon when choosing a light for your aquarium, yet is often over looked by both marine and freshwater pant keeping aquarists."

That mean bulb with higher Lumens will be also higher in PAR on same lighting area.
Right ? 

Cheers
A


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## ceg4048 (23 Jun 2010)

No, that's wrong. As I stated previously, lumens have only to do with human perception, not with photosynthetic activity. This is not to say that there is no overlap, only that you cannot predict the photosynthetic potential of a light source using Lumens.

The human visual cortex is optimized around the green and yellow frequencies. That means we have very good response to these wavelengths, in the neighborhood of 500 nanometers. It also means that we do not have a very good response to red (700 nm) or to blue/violet (400 nm).

Therefore, it is entirely possible for a bulb that has a lot of blue/violet and that does not have a lot of green/yellow to have a higher PAR but that will look dimmer to us. Because lumens is essentially a measure of how much green/yellow the bulb contains then that same blue/violet bulb will have a low Lumen rating but will have a very high PAR value.

On the contrary, you can have a bulb that has high green/yellow content which will produce a higher Lumen rating than the first bulb but this bulb could easily have a lower PAR.

PAR grows plants, not Lumens. So when you need a light that will be bright to your eyes, say a bulb for lighting your driveway, then yes, you want as high a Lumen rating as you can get for the given wattage. But blue light has higher energy than green or red so that bulbs with blue, although they will look dimmer to us and would not do as good a job of lighting the driveway, may actually deliver more energy to the leaf.

One of the things that the energy saver bulbs will claim is that they have a lower wattage but that they produce light of a higher wattage bulb. One way they can do this is to tailor the bulb to emit more of it's energy in the 500nm region which your eyes will be more sensitive to, thereby giving the illusion that they are as strong as a higher wattage bulb. The bulb that they are comparing themselves to will be bulbs that emit in wavelengths further in the red or blue part of the spectrum.

Lumens, Lux, Kelvin and CRI are only relevant to our perception of light and are measurements of this perception. Again, this does not mean that any given bulb with a higher Lumen rating than another given bulb is necessarily weaker, only that you cannot predict the effect of photosynthesis using this measurement alone. PAR means Photosynthetically Active Radiation. Iit absolutely does not mean Lumens per watt. It is a direct measurement of the number of photons crossing a unit area per unit time - and this is exactly the measurement that counts for plants. If the Lumen value of a bulb happens to be higher than an lesser PAR rated bulb then this is a coincidence based on the wavelength distribution of that bulb but it can never be a correlation across bulb types. The Lumen value will have an effect on your perception of the light in the tank. A bulb vendor can design the emission spectrum of the bulb such that there is a high green/yellow content. The bulb will therefore _appear_ to have better penetration, again, because your eyes will be more sensitive to that part of the emission. Plants and algae do not care what looks brighter to you, or what appears to have better penetration to you. They care about the total spectral energy. They care about PAR.

The technology of the bulb also determines how much of the bulbs energy is PAR energy. An incandescent bulb only has about 5%-10% of it's energy as PAR energy. The remainder of it's emissions is as infrared. That means a 400 watt incandescent bulb only has about 25 watts of useful PAR. Fluorescent and halide bulbs emit a much higher percentage of useful PAR, somewhere around 30%-40%. A typical 400 watt Metal Halide bulb will emit somewhere in the neighborhood of 150 watts of PAR energy. This is one of the reasons that fluorescent bulbs run much cooler than incandescent bulbs, because they emit more of the input energy in the visible spectrum and not as infrared (heat).

That's why it's very difficult to compare bulbs of different types. You cannot directly compare a halide bulb with a T-12 bulb unless you measure their relative PAR values. It's even difficult to compare bulbs of the same technology simply because the the emission spectrum of the bulbs may differ vastly. Therefore, if you want to compare bulbs for human activities such as photography or aesthetics or driveway lighting, then measurements such as Lumens, Lux, CRI and so forth are relevant. If you want to compare bulbs for the purpose of photosynthetic organisms, and specifically for plants, then you have to limit your comparisons to Photosynthetically Active Radiation measurements.

Cheers,


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## arty (23 Jun 2010)

Okey 
Do You think in this situation with less lumens bulb will be higher in PAR ?

Cheers
A


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## ceg4048 (23 Jun 2010)

Oh golly, no one could say. It could easily be that the 4750 Lumen GE bulb has a higher PAR than the 4050 Lumen Sylvania bulb. The opposite could be true, or they may have identical PAR outputs. Any one of these possibilities could be true and would not at all be surprising. The only way to tell is to use a PAR meter. It would be nice if vendors added this parameter to their bulb ratings but we are the only fanatics that really care. In any case, from the PAR measurements I've seen of various T5 bulbs, in general the bulbs are likely to be very similar in PAR if they are of the same wattage. You won't see any difference in growth performance unless you did specific, tightly controlled tests. The energy decays as a function of distance from the bulb (and as a function of time), there are reflections from nearby surfaces, the plants are constantly growing and changing, so whatever minor differences exist in closely matched bulbs will disappear.

That's one of the reasons that we suggest you simply look at James' sticky and get the bulbs that you like the look of, because you will not see performance differences unless you change the wattage significantly. You have to look at the tank and enjoy the colors that you see. It's no point getting a higher PAR bulb if the colors are ugly. I think that's one thing you're not considering. These bulbs could be radically different in appearance. Just because they each have a 6500K label on them it doesn't mean that they are similar in appearance. Neither bulb actually emits at 6500K, this is just more marketing hype. 

Furthermore, there are more things that will have an effect on growth performance, like flow/CO2, than will any minor differences in PAR values or spectral distribution curves between similarly spec'ed bulbs. 

Cheers,


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## arty (23 Jun 2010)

Real Thanks for Advice. You are good ceg4048.


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## chilled84 (22 Jul 2010)

ceg4048 said:
			
		

> No, that's wrong. As I stated previously, lumens have only to do with human perception, not with photosynthetic activity. This is not to say that there is no overlap, only that you cannot predict the photosynthetic potential of a light source using Lumens.
> 
> The human visual cortex is optimized around the green and yellow frequencies. That means we have very good response to these wavelengths, in the neighborhood of 500 nanometers. It also means that we do not have a very good response to red (700 nm) or to blue/violet (400 nm).
> 
> ...



This artical has cleared up a lot and has made me understand lighting values  a great deal! what a helpful write up. Thanks again CEG!


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## Mark Green (24 Dec 2013)

> No, that's wrong. As I stated previously,
> lumens have only to do with human perception, not with photosynthetic activity. This is not to say that there is no overlap, only that you cannot predict the photosynthetic potential of a light source using Lumens.
> 
> The human visual cortex is optimized around the green and yellow frequencies. That means we have very good response to these wavelengths, in the neighborhood of 500 nanometers. It also means that we do not have a very good response to red (700 nm) or to blue/violet (400 nm).
> ...


 
What a great article, ive just learnt my one thing for the day...

Thankyou Ceg4048


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