When I first started with saltwater I used 3 x T12 40 watt cool whites and one true 03 actinic. Then came compact fluorescent, Metal Halide, T5HO, and now LED.
The T12 Combo looked okay but not enough power. I grew SPS under CFL’s but they could not hold the gas required for Fluorescents so they did not last past 8 months before dropping off a bunch. When T5HO’s came out all you heard was how MH was dead technology and T5HO was the future. Well MH is still here and is so far ahead of T5 it is not funny when it comes to lamp life with certain lamps/ballast combos. Over the years I first used Coralvue Reeflux lamps which are Pulse Start just like the Radium. If you place a Reefflux lamp on a probe start magnetic ballast, it will be 25% dimmer than on an electronic ballast. I have never run a Pulse Start magnetic ballast so I am not sure but it should be comparable to the electronic? With Reeflux lamps they were lasting 18 months with only a 10% drop in light output and no spectral shift. With Radium I have had one out of six that dropped 10% after 12 months, but most last past 18 months with one that I have is around 24 months. All these lamps where protected by either a glass lense (Luminbright Pendant) or glass tops on my aquarium. When I had them in a canopy where moisture was present lamp life dropped 30%. With T5HO’s 12 months has been the max life I can get out of ATI or any other lamp whether they are protected or not. When you have a 4 lamp fixture it becomes a $100 dollar bill to change lamps that gets expensive every year.
LEDS well when the first ones came out super bright, but only used blue and white with no color and vey little PAR. And all you heard was “PAR meters don’t work with LEDS”. You could have used the same argument with a 20K MH Lamp, except for the Radium(which is closer to a 12K) because most of the 20k lamp is in the 450 range and there PAR readings sometimes are half of a 10K. Today’s Leds are much better with PAR readings, plus they are using full spectrum LED’s. The original LEDS were also too intense, and most are probably asking “well what does that mean”? There are two meters we use in my industry, Foot candle/LUX (How Bright) and PAR. I have a Reef Capable LED third generation, first one lasted two months, second lasted one week. This one has lasted over a year with very little drop off. PAR reading on top of the tank is 200 and 14 inches down 100. Not the greatest, but using a foot candle meter I have 4000 foot candles on top! Now what does that mean comparing to a MH, to get a 4000 foot candles I have to use a DE MH 400w lamp. My 250 watt radiums are 2500 foot candles with a PAR reading of 1900 at the top of my tank. I actually burned a green birdsnest that was farther up in my 40 gallon breeder with the Marineland fixture. And even with the lower PAR reading I had Tricolor SPS that did very well. If there is one thing that LEDs have taught us is we do not need a ton of PAR to grow corals. On my 300 gallon I have 3 x 250 watts of Radium lamps that produce a PAR reading of 200 in the bottom far corner and I grow beautiful green birdsnest in that location.
I think where people are having issues with LEDs is having too many choices on what look they want versus what your corals need. Does anybody take a spectral graph or PAR meter when adjusting their high dollar fixture? I doubt it, plus we are so worried about ramping up and down that our corals probably only get 4 hours of max light from the LEDs because the rest of the time we are at 40% with that cool dimming feature. Whereas on my Radium MH my corals are getting 10 hours in the winter time and 8 in the summer of 100%.
As most of you know I use a Build my LED fixture on my 125 (6’) tank at work. The PAR levels are pretty good. I grow algae on the front and back of the tank with no shadows using 90 degree lenses. I have softies and photosynthetic Gorgonians that are doing well with only using 100 watts for a 6’ light fixture running at about 85% and glass tops( I don’t want any moisture getting to this fixture and as I have learned with MH the protection will help them last longer). With the glass tops I do lose 10% of the light. Fish look as good if not better than under my ATI T5HO lamps. I understand Build My LED is now making an LED fixture that mimics a Radium lamp which I am dying to try out once my daughter graduates college. I run my LED fixture 12 hours a day.
In closing the same testing company that claims LEDs last 50,000 hours also has tested T8 lamps at 30,000 hours and MH with pulse start lamps and ballast at 20,000 hours. The average LED will drop 3% per year so if you run them at 80 – 85% you can raise them each year to maintain the same lighting levels for at least 4 to 6 years. One last thing a lamp at 4000 foot candles looks just like a lamp at 1500 foot candles, your eyes cannot tell the difference but your corals sure can. And a Radium lamp that is 24 months old looks exactly like one that is a few weeks old, only a meter can tell the difference.