# LED reviews, merrits and marketing



## Flygirl (Jul 23, 2011)

Lighting has always been a topic of interest and maybe in the past one of a bit less ambiguity. Now, with the LED revolution in aquarium lighting products I'm finding it tough to really know what is good, what is not so good and of course the why. How and what can we use to compare the different products form the various manufacturers, especially with the huge swings in prices between them. What are the options for educating ourselves about the products and their merits. Obviously the net is huge source of information, and forums make up a good portion with the reviews.

In my quest to be better informed about LEDs for our tanks, I came across an article that was quite enlightening. I guess a question I never asked myself before was, what is the motivation of those recommending or negging a specific product, especially the staff. 
The Truth About Orphek & Aquarium Product Marketing - Captive Aquatics: An Aquarium and Ecology Blog

Aquarium lighting has never been cheap, especially if you're looking for either planted or reef, and as such knowing a bit about your investment in advance pays in the long run. Is there an effective and simplified "tick in the box" criteria similar to what we have for fish i.e. perky, swims upright, has no white spots, eats, clear eyes etc. that would help to see how lights measure up against each other and what is worth the extra dollars.

What have you guys found?

Any good websites/blogs that can shed a bit of light on the subject?


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## neven (May 15, 2010)

I wondered why I couldn't find much info on the lights charles carries on the reef sites, now I have my answer. But I understand where that article comes from, the planted tank is rampant with that behavior.

Now led lights, there are too many factors. You have several leds from the same manufacturer with the same wattaage yet lumens vary greatly, and then you have varying optics. With all these variables, only par and light spread are what we really care about.

What is needed is for companies to drop lumens and watts, and establsih a standard listing for par, similar to what pumps use for gph vs head. We need par to height. The optics help let us know the light spread, so that variable can stay the same, but atleast par would be measured


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## Jasonator (Jul 12, 2011)

Good review = always good to have more opinions.
I emailed the author for advice on the best lights for plants and fish. We'll see....


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## Algae Beater (Apr 21, 2010)

Largely the expectation is that the consumer will do their research. LED technology has many variables and pitfalls. I’ll lay out some basics here  

One must consider how hard the diodes are being driven, as most lumen per watt ratings are at max load. I would venture to say that most manufacturers try to drive the LEDs at max to squeeze the most PAR out. this typically can shorten diode lifespan without VERY powerful passive and active cooling (heat sinks and airflow/liquid cooling in some cases) a minimal drop in power to the diodes lowers light intensity slightly in most cases less than 1% but can greatly extend the life of the diodes. 
The most efficient LEDs are those of lower wattages. IE lower than 1 watt each. As a drawback their intensity and par suffers significantly. You need quite a few of these to equate to a high wattage, albeit less efficient LED. In general most fixtures will use 2-3 watt LEDs. They are a nice marriage of efficiency and output/intensity. Using a whole heap of lower wattage emitters DOES NOT equate the light produced by fewer higher wattage diodes. Intensity is most important for penetrating deep into tanks. This is something that lower wattage diodes SEVERELY lack. 
Optics are one of these features that have their place, but far too many companies use them to make inferior, under powered fixtures somehow passable. In situations where directional light are needed or the fixture needs to be high above the tank, or to avoid spillage of light then lenses can be very useful. Most aquarists keep their light fixtures a few inches above the surface of the water. This makes tight angle lenses useless. But many people use them. Without optics, LEDs blend much better and provide more even lighting with a much better spread as primary optics that the diodes are manufactured with is ~120degrees. But the majority of light manufacturers use optics for marketing purposes rather than performance. 
The most significant difference in LED fixtures is heat management. Heat is the most detrimental force to LEDs. With too much heat LEDs become less efficient and can be damaged / greatly shortened lifespan. First and foremost there is passive cooling or heat sinks. This is a fixture’s ability to dissipate heat without the use of fans. This is achieved with aluminum shaped into thin fins and shapes with high surface area. Aluminum is pricey and hard to work with. It is for this reason that cheaper and less reliable LED fixtures use active cooling methods such as fans and liquid cooling techniques. Active cooling is ultimately mechanical using motors to move air of liquids to remove heat from the LEDs in a high humidity environment the reliability of motors is greatly reduced. It is not a question of if the fans of pumps will fail, but rather when. When failure occurs, cheaper fixtures without proper passive cooling in place will fail. It is at this time that the need for heat sinking and that fancy aluminum shell becomes painfully apparent. If you want to find a well designed fixture, pick it up! If its heavy, chances are it has a well-designed passive cooling system. 

LEDs lack in spectral output individually. White coloured LEDs are full spectrum but lack in photosynthetic active radiation (PAR) or wavelengths of light that plants and corals use to grow and survive. It is for this reason that most manufacturers offer a myriad of LED colours to be used in combination to create a desired light. Here is a list of typically used diodes:

Most manufacturers use a combination of the following LED colours
Warm white – typically around 3500K and very yellow in a appearance and very high in red light spectrums. This type of diode has the HIGHEST cri (colour rending index or how closely the light resembles midday sunlight on a scale of 1 to 100 ). Warm white LEDs have a CRI greater than 80. 
Nuetral white – Sits at around 5000K with a slightly warm daylight appearance think of it as a mix between warm and cool white. 
Cool white – Very common in light fixtures. Has Higher Kelvin daylight with more blue light in its spectrum 8000-10,000k. It has a very crisp daylight with a hint of blue. 
Blue – These LEDs are generally in the actinic wavelength at around 420 nanometers and are high Kelvin 20,000+K. They create that stunning fluorescence in corals. This is typically the colour used in blue moonlights.
Royal Blue – These diodes are similar to blues however their spectrum is closer to 460nm. Generally these are used for colour enhancement as the fluorescence they produce is VERY attractive.

The following LEDs are used in some cases for colour enhancement or in combination with many colours to create an RGB white light (like your TV) 
Red – This type of LED is used for colour enhancement or fish, plants, corals and other invertebrates. This diode’s output is around the 650nm mark for spectral output. It is also a integral component of photosynthesis. It has very low penetration through any height of water as H20 is very efficient at absorbing red light. 
Orange – This colour is the same as red but lower in wavelength, around 640nm. It is not commonly used in aquarium fixtures. 
Amber – This colour has a slight amount of red in its spectrum which has a slight effect on PAR or useful light. It is mostly comprised of yellow wavelengths. For the most part it is cosmetic and used for colour enhancement. This type of LED has a wavelength around 590nm.
Green – this colour of LED does nothing for PAR and is used for colour enhancement. The spectral output of this LED sits at about 530nm.
Cyan – This type of LED is basically the same as green LEDs for its functionality. Its spectral output is slightly bluer though, with is spectral peak at 510nm.

hope all of this helps!


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