I’ve been obsessing about marine lighting for some 25 years now and during that time I’ve run them all. T12, T8, T5, Power Compact T5, Metal Halide, Mercury Vapor, passive, and actively cooled LED. Even Plasma. Remember those? And I’ve always been quick to try out the latest models and technologies.
I remember the skepticism around T5 and the even greater skepticism around LED, some of which still exists to this day. Now T5 is seen as probably the most reliable, foolproof way to grow corals, and LED is often now compared to T5 both in spectrum and coverage.
In the early days of LED we were sold on cost savings and even saving the planet versus lights like fluorescent which contain mercury. We could light our reefs for a fraction of the running costs and recoup our investment over the years by spending less on running them and not having to change out the bulbs every year.
And in the early days, it was just a straight PAR race with LED too, making sure they could penetrate down to the depths of our reef tanks and be physically bright enough to light corals. Lenses were the name of the game to the point where corals placed high were bleaching after changing over to high powered LEDs, versus T5. Branded diodes from CREE and Osram helped lend credibility to the technology in the units, controllers came in, enabling dimming and even spectral shift and the aquarium LED revolution was born.
The first, most notable difference was the lack of heat generated by LED versus T5 and halide, so small, bright clusters of LEDs could be placed together, also enabling the nano reef revolution.
But some LEDs were narrow in spectrum and it showed both in color rendition in the tank and lack of growth in some coral species. The temptation was to up the output to 100%, and Royal blues were introduced to create pop and aid washed out Cyan diodes, followed by red, green and violet. We studied the broad spectrum of sunlight versus the very narrow peaks of LEDs and sought to fill the spectrum over our tanks one differently colored LED diode at a time.
Disco and demo modes were all the rage and our tanks would rarely have the same settings for more than a few hours as we constantly changed colors and programs for the simple reason that we could, and we’d never been able to before. Stand behind tank onlookers with wi-fi control from your phone or tablet and you were the coolest reefer in town. Do you actually use lightning mode or cloud cover these days? Or even moonlight?
But look at the most successful LEDs now and they’re the ones that provide the fullest spectrum and the most even coverage. Lighting a reef with sharply defined cones of light isn’t easy because the corals directly underneath get blasted while those on the periphery of the cones battle shadow, uneven lighting and low par. Add some red and color mixing also becomes a problem.
Look at wattage too. Twenty years ago I lit my 5x2x2’ 150 gallon tank with twin 150-watt metal halides accompanied by twin 30-watt T8 actinic tubes. That’s 360 watts. Then five years ago I lit the same size reef tank with 2 x Kessil AP900 at 185 watts each (=370W).
And if I wanted to light it now my options would include anything from 2 x AI Hydra 64 at 135 watts each (=270W) 3 x AI Hydra 32 at 95 watts each (=285W) 2 x Kessil AP9X (=370W) 3 x A360X (=270W) 2 x Gen 5 Radion XR30 (=360W) 3 x Gen 5 Radion XR15 (=270W) or more if I wanted wall-to-wall SPS. So I can save almost 100 watts if I have to but I if want the most evenly lit tank with XR30s or AP9Xs I’d be looking at the same energy consumption as I used twenty years ago.
Look at the recent launches of the EcoTech radion Gen 5, ATI Straton and Philips CoralCare Gen 2, and to produce the most even light spread they have all opted for a large surface area populated with lots of LED chips to illuminate a large area of reef tank and eliminate hotspots, just like T5. And Philips and ATI (both fluorescent tube manufacturers,) have also opted for built-in diffuser plates for even flatter light. A long way away from those piercing point source lenses.
A large surface area also means better escape of heat so Philips and ATI have even done away with the active fan cooling too, meaning quieter, more water-resistant lights and one less component to go wrong. Combine the spectrum and coverage of T5 with the cool running and control of LED and it should tick the boxes even of the most die-hard reefkeepers.
The evolution of aquarium LED lighting has been interesting both to watch and participate in, but the bit I find particularly interesting now is that we are back to similar wattages and larger, flatter units with wide spectrums in order to get the best coral growth. The same has happened with plant LEDs too.
And, although many reefers may view them as second class in terms of quality, the Chinese-made black boxes have always made units this way, with many users swearing by the results they can produce. So forget all the special effects, a unit with a wide spread and spectrum is all I need for my next tank. And as tempted as I am by LED/T5 hybrid units, will the new generation of LEDs negate the need for them too?
But if one thing is certain in reefing, its that lighting evolution (and debate,) will continue.