Is LED lighting just a fad or now a good replacement for T5 (actinic) bulbs? what do I need to look for in a LED light?
LEDs or "light-emitting diodes" have been around for decades, serving as the little green and red lights that indicate power to plugged-in items. As energy-efficiency became more of a social watchword, LEDs began to evolve to serve greater purposes. Flashlights, advertising signs and even taillights on vehicles were converted to clusters of the tiny diodes, not only because of their extremely low energy consumption but for their working lifespan, which can reach into the tens of thousands of hours. Only in the last five years or so have the fixtures and the diodes themselves been improved to a point where they can emit a comparable volume of light as a T5 or Metal Halide fixture.
It's a relatively easy equation to determine if you'd benefit consumption-wise from using LED. Figure the cost of the unit and its average power draw gauged to the total hours you'll have it working. Obviously you already have a light fixture of some sort, so figure its average power draw as well, and also include the cost of annual replacement bulbs for as many years as HALF the working life of the LED.
If the equation is weighed heavily to one side, consider that option. If not, it becomes a personal preference. Many people stand by the adage "If it ain't broke, don't fix it." For what cost reduction are you willing to dismantle a system that you have absolute proof works and allows your corals to thrive over a several-year span?
The only drawback to the LED phenomenon is that there is no consensus of long-term data. Since fixtures, diodes and spectrum have improved rapidly over the last couple years, there are not sufficient reported results of success on any one of them to be a reliable influence on your decision. Most results reported have been from hobbyists, and have little to no actual scientific quantification outside of perhaps par readings. The other reported results must be considered carefully because they may come from vendors, sponsors, or manufacturers trying to push their new technology.
To prove that LED fixtures are really capable of sustaining a reef over their entire lifespan, in my opinion, will take a few more years. For example, some of the earlier LEDs showed amazing promise over the first year or so, but then growth of SPS began to taper off and falter. In order to prove LED efficacy, hobbyists will need multiple unbiased reports of success across multiple LED platforms over multiple years.
As far as what to look for... Your LED fixture should have all of the features you expect from typical lighting fixtures, plus the bonus of a DIMMER. The dimmer will prove extremely useful for converting the tank slowly from its current lighting to its new LED. As with any high-dollar item, consider the manufacturer's reputation and longevity in the industry, the quality of workmanship and reviews of the product, the features, and the warranty.
That's a pretty good reply. I have a 120 (until later today) that I had 2x250W MHs, and 2x96W PCs. I DIYed my own 96 Cree XR-E LED system for about $1100. LEDs are not cheap up front. However, I don't think they're a "fad" unless our energy issues are going to suddenly disappear and it's cost plummets...
Taking operational cost, and regular bulb replacement into consideration I calculated approximately a 3 year payback using the actual kWh usage of the new fixture. Since I added an Apex controller, I expect that payback to be even shorter, for the LEDs, due to lower power consumption due to daily dimming. www.rapidled.com has a new PWM dimming module to control sunrise/sunset for about $60.
I found that driving my 96 LEDs at around 60% of their maximum provides all of the intensity I need with the 120. I'll be reconfiguring them next week to light the 210 I'm swapping the 120 for today and believe I'll have more than plenty of light to keep all of my SPS... for under 300W power consumption when I ramp them up a bit.
Junior??? Are you kidding??? I was on the old forum here before I joined RC back in 2000.
I definitely agree that operating and equipment costs for the LED systems are in the long run lower than those of any other type of reef lighting. The only concern that I have with LEDs is that they are a new method of delivering radiation, and that there is not any sort of long-term evidence that can demonstrate that LEDs will maintain healthy photosynthetic processes in a mixed reef setup for any substantial length of time. Visible intensity is only one aspect of lighting that needs to be addressed. I cannot disagree that LEDs produce a beautiful light and are cost effective. I only caution reefers to remember that success in the hobby should not be measured in months, it should be measured in years.
Since LED questions seem to be appearing in all of the forums, I am posting a link to Sanjay Joshi's work with LED testing. All of Dr. Joshi's prior work and articles can be browsed at Advanced Aquarist.
This first link is to a quantitative COMPARISON between T5, Halide, and LED: http://www.advancedaquarist.com/2010/2/aafeature2
These next two links are to his performance tests of several of the major brands of LED fixtures:
Hopefully these will help everyone!
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