Serious question: Are LEDs actually more efficient than T5 or MH?

[Oliver P.]

Hi,

a man in Switzerland made a big comparison of different Fixtures and light sources. He made PAR-readings below all fixtures and compared the results of his PAR-Readings to the energy-consumption of each fixture. In this way he got results for efficiency in "Par per Watt" . Here is the summary:

The man is known to be the "german" Sanjay Joshi. He use a Spectrometer and compared all fixtures at the same distances and circumstances. But the most interesting thing is that there are so different results. Some LED-Fixtures are very efficient and some LED Fixtures are not more efficient than T5 (for example). So you cant say that LED-Fixtures are in genral the most efficient Solution. It really depends on the technical solution of each fixture.

But the technical efficiency is just one part of the story. Much more important is the "biological" efficiency. Especially for corals. With "biological" efficiency I dont mean PUR or Photosynthetic Usable Radion. PUR only refers to the spectrical distribution of light. An important Factor is how the light hits the corals. Please think about the self shadowing effect of:
1. directional light comming from a smal more punctual light source or
2. more diffuse light comming from light source that covers your complete Aquarium.

It is known that too much light from one direction means Stress for corals. The side of the coral that shows to the light source gets too much light and the other side of the coral that shows to the opposite side of the light source get not enough light (dark brown part of the coral). This is Stress for corals and like most of us corals dont like stress, too.
But if the light hits the coral from different directions (more diffuse light with less self shdowing effect on corals) the coral is able to absorb more light with its complete surface (epidermis) and to use it for photosynthesis. In this way we avoid dark areas on the corals.

So, it is not just imporatant how much PAR we have in our Tank or which light source is more efficent. It is imporatant that we illuminate our corals in a natural and "coral-friendy" way.

regards,
Oliver

 

[GroktheCube]

Hi,

a man in Switzerland made a big comparison of different Fixtures and light sources. He made PAR-readings below all fixtures and compared the results of his PAR-Readings to the energy-consumption of each fixture. In this way he got results for efficiency in "Par per Watt" . Here is the summary:

The man is known to be the "german" Sanjay Joshi. He use a Spectrometer and compared all fixtures at the same distances and circumstances. But the most interesting thing is that there are so different results. Some LED-Fixtures are very efficient and some LED Fixtures are not more efficient than T5 (for example). So you cant say that LED-Fixtures are in genral the most efficient Solution. It really depends on the technical solution of each fixture.

But the technical efficiency is just one part of the story. Much more important is the "biological" efficiency. Especially for corals. With "biological" efficiency I dont mean PUR or Photosynthetic Usable Radion. PUR only refers to the spectrical distribution of light. An important Factor is how the light hits the corals. Please think about the self shadowing effect of:
1. directional light comming from a smal more punctual light source or
2. more diffuse light comming from light source that covers your complete Aquarium.

It is known that too much light from one direction means Stress for corals. The side of the coral that shows to the light source gets too much light and the other side of the coral that shows to the opposite side of the light source get not enough light (dark brown part of the coral). This is Stress for corals and like most of us corals dont like stress, too.
But if the light hits the coral from different directions (more diffuse light with less self shdowing effect on corals) the coral is able to absorb more light with its complete surface (epidermis) and to use it for photosynthesis. In this way we avoid dark areas on the corals.

So, it is not just imporatant how much PAR we have in our Tank or which light source is more efficent. It is imporatant that we illuminate our corals in a natural and "coral-friendy" way.

regards,
Oliver

Great data Oliver, thank you!

That definitely helps paint a clear picture.

 

[gcarroll]

Hi,

a man in Switzerland made a big comparison of different Fixtures and light sources. He made PAR-readings below all fixtures and compared the results of his PAR-Readings to the energy-consumption of each fixture. In this way he got results for efficiency in "Par per Watt" . Here is the summary:

The man is known to be the "german" Sanjay Joshi. He use a Spectrometer and compared all fixtures at the same distances and circumstances. But the most interesting thing is that there are so different results. Some LED-Fixtures are very efficient and some LED Fixtures are not more efficient than T5 (for example). So you cant say that LED-Fixtures are in genral the most efficient Solution. It really depends on the technical solution of each fixture.

But the technical efficiency is just one part of the story. Much more important is the "biological" efficiency. Especially for corals. With "biological" efficiency I dont mean PUR or Photosynthetic Usable Radion. PUR only refers to the spectrical distribution of light. An important Factor is how the light hits the corals. Please think about the self shadowing effect of:
1. directional light comming from a smal more punctual light source or
2. more diffuse light comming from light source that covers your complete Aquarium.

It is known that too much light from one direction means Stress for corals. The side of the coral that shows to the light source gets too much light and the other side of the coral that shows to the opposite side of the light source get not enough light (dark brown part of the coral). This is Stress for corals and like most of us corals dont like stress, too.
But if the light hits the coral from different directions (more diffuse light with less self shdowing effect on corals) the coral is able to absorb more light with its complete surface (epidermis) and to use it for photosynthesis. In this way we avoid dark areas on the corals.

So, it is not just imporatant how much PAR we have in our Tank or which light source is more efficent. It is imporatant that we illuminate our corals in a natural and "coral-friendy" way.

regards,
Oliver

Is there a reason the area measured was a rectangle? Why not a large square like Sanjay does (26" x 36")? It seems to me that some of these fixtures would be at a disadvantage depending on their size and optics. Especially if they were capable of lighting area outside the measurement field. What was the distance of the light to the meter? Can you give a link to the test?

 

[CoralsAddiction]

Serious question: Are LEDs actually more efficient than T5 or MH?

If you can say that not having to buy T5 light bulbs every 6-12 months is efficient then I would say yeah. I've never had anything but LED lights and would not consider switching to T5s. My SPS, LPS and Softies grow really nice under my Kessil so I don't see why use T5.

 

[Oliver P.]

@gcarroll
you can find all detailed informations here:
http://hennings-miniriff.jimdo.com/vortrag-sindelfingen-2013/module/vorstellung-module/
Unfortunately, most of the explanations on his webside are only in german and you have to search to find all information.

I cant say why the measured area was a rectangle. May be he thought that most aquariums are more like a rectangle and he wants to find the best solution for a typical Aquarium. But the area is not too smal in my opinion. Most of the fixtures are measures in an area of 84 x 60cm or 24" x 33" and he made measurements in different distances (12", 18", 24).

You are right that some fixtures (especially Fixtures with a wide spread angle) would be at a disadvantage if a part of the light is outside the measurement field. I guess that this was the reason why he took the PAR-Readings at a distance of 12" for comparisons in his summary. In this way he can avoid this effect.

But be that as it may, I thought that it was worth to share this informations here.
To do all this measurements is a lot of work ....

But again. This is "only" the technical efficiency. We really need to consider what kind of light is the most "coral-freindy" light. Otherwise it comes more or less to disadvantages for corals.

If you can say that not having to buy T5 light bulbs every 6-12 months is efficient then I would say yeah. I've never had anything but LED lights and would not consider switching to T5s. My SPS, LPS and Softies grow really nice under my Kessil so I don't see why use T5.

It is important to understand the needs of our corals with respect to light. I offen see discussions here where people get lost in details (I am sorry to say this). But once you know what really counts for corals, you can generate this kind of light with different light sources. It is not T5 against LED or MH. In days like these, where the market is flooded with so many different fixtures it is important to keep in mind what corals really need (IMMO).

For corals it is important to get the right Spectrum (much blue) in the right dosage/Intensity (PAR 300-700 for example) and to get this light from different directions (less self-shadowing effect). This is important for corals. If you can generate this kind of light in the same way in your complete aquarium (even light distribution without "Hotspots") than this is an extra bonus and gives you the possibility to be more flexible to place corals. If you can generate this kind of light with less energy, than this is another extra bonus.

regards,
Oliver

 

[Big E]

It is important to understand the needs of our corals with respect to light. I offen see discussions here where people get lost in details (I am sorry to say this). But once you know what really counts for corals, you can generate this kind of light with different light sources. It is not T5 against LED or MH. In days like these, where the market is flooded with so many different fixtures it is important to keep in mind what corals really need (IMMO).

For corals it is important to get the right Spectrum (much blue) in the right dosage/Intensity (PAR 300-700 for example) and to get this light from different directions (less self-shadowing effect). This is important for corals. If you can generate this kind of light in the same way in your complete aquarium (even light distribution without "Hotspots") than this is an extra bonus and gives you the possibility to be more flexible to place corals. If you can generate this kind of light with less energy, than this is another extra bonus.

Yup, I've been saying this for two years and it's finally starting to sink in with more people.

Because of the design of some LEDs with respect to type of diode colors, number of diodes, configurations, actual coverage, ect. it's a much tougher challenge to get it right.

Now, add hundreds of configurations that some of the software gives you and it's no wonder there are problems, especially when it comes to Acropora corals.

Whatever lighting you're using you want to limit the variables down to as few as possible. Correct spectrum, coverage are most important........if you've got this consistent across the tank without hot spots, placing corals is easy with regards to par/intensity and duration.

People would have a lot more success in getting the above right and quit messing with all the controls. Turn them on and off with the same spectrum set up & intensity that works. Most of the controls offered are toys..........think about what the corals need.