Under Construction More to come
We recently decided to evaluate our LEDs to determine which one is best and the answer was still ambiguous and can be debated in many different ways. This said here is our comparison and methodology.
First some assumptions and definitions:
Not all 400 watt MH lights are the same nor produce the same PAR not all MH ballasts are as efficient as one another.
60 XP-E Regular or XR-E Q5 LEDs with 70 degree optics on a 24″ heatsink produce the same PAR as a 400 watt Radium. This we chose as a baseline based on our direct PAR measurements.
Drive current 700mA : Whats normally used by reefers for LEDs of this class execpt XP-G 1050 mA and X-ML which 2000mA is our max recommendation based on direct discussion with Cree representatives …
Note: Based on efficiency and thermal management 1660mA is our recommendation for the Cree XM-L
Lumens: From product PDF Data Sheets based on charts or interpolation of tested and normal drive current.
AVG Lumens per Watt: Based on 3.2 forward voltage for Cree and 3.4 forward voltage for Bridglux applied to standard drive current. Lumins was divided by this.
Sample Fixture Watts: Based on a 60 XR-E LED Fixture with 70 Degree Optics. The watts are an estimation of the total watts of the number of LEDs required to produce a similar PAR to the 400 watt Radium. Reference https://reefledlights.com/optics-evaluation/ Our newer gen of fixtures with the Â XP series and Carclo Optics preform better.
This section is based on the practicable application of readily available products. Here you can see the fixtures are 12″ above the water line so we put tighter beam optics(Carclo Frosted Wide) to focus all the energy into the tank so nothing gets wasted. The Yellow pic is the overall spread of the light. The red pic is the realistic spread. Below is the Carclo XP-E Frosted Wide chart
As you can see from the pics below the light your corals are receiving can be misleading. The following pics are a comparison on the actual vs the tertiary light your reef receives.
Take it one step forward and tilt your fixture 10-15 degrees on a standard tank with live rock stacked to the back of the tank and LEDs offer you the most efficient and tailored light to your system.
Carclo Frosted Wide
31.5 50%< power
78.1% effective lighting
Red LEDs in a reef tank?
What depths do the typical corals in our tank originate.
Euphyllia Coral Habitat: The E. fimbriata live in colonies in waters that are turbid, yet gentle. They are found at depths down to 131 feet (40 m) and enjoy indirect bright light. They have stinging cells to help capture small prey and to defend themselves against predators.
Acanthastrea Coral Habitat: The Acanthastrea echinata live in a wide range of habitats on the reef, and are found at depths of 0-98 feet (0 – 30 m). They rarely occur over 3 feet (1 m) in diameter. They feed at night, extending thick tangled tentacles.
Bubble Tip Anenome
Sea Anemone Habitat: Bubble Tip Anemones are widespread and common. They are found intertidal zones to depths of 130 feet (40 m).
Birds Nest SPS
Seriatopora Coral Habitat:The Seriatopora genus are found in depths from 0 to 131 feet (0 – 40 m) in shallow reefs and upper reef slopes. S. hystrix inhabit shallow reef environments throughout the full range of the genus at depths of 20 to 115 feet (6 – 25 m).
Idaho Grape Montipora
Montipora Coral Habitat: M. undata are found on upper reef slopes in water that is moderately turbulent, and at depths from 9 to 82 feet (3 to 25 m). Montipora, as a species, are found from deep water (greater than 10 meters / 33 feet) to the reef crest and from clear oceanic reefs to turbid (not clear because of stirred-up sediment, etc.) lagoons. Even though their range is large, Montipora are more likely to be found in quiet water at mid-depths.
A BIG thanks goes to http://animal-world.comÂ for sharing this information.
Sanjay Joshi, Ph.D http://www.manhattanreefs.com/lighting wrote a fantastic article comparing Metal Halides to Natural sunlight and its spectrums at various depths of the ocean. His research has been instrumental in our led recommendations.
The Graphic he produced that we are referencing as follow shows at 10meters you can see how there is no 610nm spectrum (what would be red LEDs) at those depths.
We thankful for the valuable research of Sanjay and many others who have helped us to put our packages together. We studied the best bulbs used in our industry and selected specific bins of LEDs to follow along the same curves.
When choosing the best LEDs for coral growth we considered the needs of the zooanthella algae. Zooanthella Algea are the symbiotic algae found in photosynthetic corals. They provide the coral with food from photosynthesis. Below is a graph of the light spectrum that they use (ref blog.captive-aquatics.com)
Both chlorophyll A&B are receptive to the 440-480nm wavelength. Our Premium Royal Blue LED is 450nm which works well for both chlorophyll A&B. The Cree Cool White has a very nice 450nm spike with a comfortable 500-650nm hump. The warmer bins of the Cool White have more in the 600-650nm. 600-675nm is a great grow spectrum. In fact many nuisance algae grow quite well in this spectrum. Below 30 meters this spectrum is virtually non-existent in the ocean and below 10 meters is severely limited. Using only two types of LEDs, Cree Cool White and Royal Blue, we have witnessed great growth in our personal aquariums without the problem of nuisance algae or cyano bacteria. Â One could add a few Reds and Blues to help but is unnecessary for growth as the coral and zooanthella algae adapt to the available light. We like to use the Blue for a moonlight and a few Reds for a High Noon Effect. Personally I really dont like the look of of too many Reds and find the colours of the corals really pop with the Royal Blue closest to 450nm. Adding other colours do little for photosynthesis but allow the hobbiest to tweak the look of their tank.
Why we dont advocate cheap heatsinks
LEDs are a BIG upfront cost when setting up your lighting solution and you need to protect that investment as we intend our customers to use these lights for the next 11 years. To help you get there you have to keep in mind that the biggest enemy to LEDs is HEAT! overheating the diode can damage the LED irrevocably and cause an unwanted spectrum shift as well as shortening their lifespan.
The heatsinks that we utilize were designed to have a thick backing where the LED star connects to so it may draw heat away from each LED and dissipate as much as possible. This is a safety in case of fan failure to protect the LEDs. The most efficient way to direct your airflow is to place the fans on top of the fins and have the fans blow into the fins of the heatsink to cool it down.
Here’s some additional reading information about thermal regulation and its importance.
“Why does thermal management matter?Excess heat directly affects both short-term and long-term LED performance. The shortterm (reversible) effects are color shift and reduced light output while the long-term effect is accelerated lumen depreciation and thus shortened useful life
Continuous operation at elevated temperature dramatically accelerates lumen depreciation resulting in shortened useful life. The chart below shows the light output over time (experimental data to 10,000 hours and extrapolation beyond) for two identical LEDs driven at the same current but with an 11°C difference in Tj. Estimated useful life (defined as 70% lumen maintenance) decreased from ~37,000 hours to ~16,000 hours, a 57% reduction, with the 11°C temperature increase.”
U.S. Department of Energy
“The most serious effect of heating LEDs is a reduction of lifetime. When overheating damages an area of a semiconductor crystal, it is likely to offer more electrical resistance. Then the area of increased electrical resistance is even more likely to overheat again, causing additional damage. Thermal degradation can reduce the operational lifetime from a potential of tens of thousands of hours to just a few thousand or even less.”
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