Lighting Chinese led

The Chinese LED's I bought from CREE work well on my main display (http://www.hero-ledstore.com/). Now provided, I bought LEDs for coral and not algae (white and blue LEDs) it could be a different story for reds but CREE seems to be an accurate manufacturer. And buying CREE parts from China is 1/2 the price! Also, if you are looking for effective power distribution, buy a DC power supply that provides say 50-75 watts from digikey, then run your LEDs through a "flexblock" (from luxdrive) which is also available from digikey. The main point being that you can use one power supply with multiple flex blocks that power different LED circuits!

 

I am using Evolution LED unit, and I can't be more satisfied.

 

Wait a minute.. Cree LEDs from China CAN be just as bad as generic LEDs from there. The reason being is Cree only sells them the diodes, it is up to the company to mount them to PCBs/Stars, and that is where the majority of failures come from. The actual emitter is Cree quality, but the overall light can be just as bad as a generic Chinese LED if it was assembled in the same plant. For me, it isn't worth it spending countless hours of my time researching which Chinese plant is better than the other... once I take into account my time, the LEDs become 2x as much money coming from China compared to buying from a trusted/reputable US based company if I want to be sure I am receiving the same quality.

 

there are many variables. How deep is your tank? What do you have in it? Do you want the same light as if you were using a metal halide or what? What look do you want, lots of blue or what?



this supplier has a good write up on it. Look under their FAQ's - LED's for the Reef Tank. If you scroll down in the article you can find a chart on size and tank depth vs. equiv. metal halide lighting. https://reefledlights.com/ledmytank/

 

That article doesn't seem to take 'spectrum' into account. Once you take that into account, and design a light around it things become much more confusing. As I have proven for years now, 50w of LED light can be = to 500w of MH. It is not possible to compare PAR to PAR between LEDs vs any other light because of the spectrum. What I have found with LEDs (using Royal blues and whites) is that as far as corals are concerned, 50w of LED light actually puts out MORE proper spectrum light than a 400w 10k MH. From my years of testing, 50 PAR at the sandbed with certain LED combinations is the same as 200 PAR from other light, and that is because the 50 PAR from LEDs is mostly in the proper spectrum for coral photosynthesis, while the 200 PAR has most of the light outside the useful spectrum for photosynthesis.

When I first got into high output LEDs, I didn't know the importance about spectrum, so I made my LED light to match my MH PAR for PAR, after the first week, 1/2 of my corals were nuked. It took me about a year of trial and error to finally realize how little PAR is needed with LEDs to equal T5 and MH light.

IMO, for a 100x60cm tank, 24 LEDs would be minimum, 36 LEDs would be max. As far as depth of the tank, that is where optics come into play, and 60 degree is the most common (and best IMO).

 

Personally, I am not a fan of the 2:1 RB:W ratio because it puts way to much 455nm (royal blue) light into a tank, which causes problems. I would actually go with a 1:1:1 ratio of 420/475 (cool blue)/Warm Whites as the primary light ratio, then add 4x 505nm cyans, 4x 630nm reds, and 4x near UV on a separate dimmable driver. The 1:1:1 ratio will provide all the light needed for coral photosynthesis. Any of the cree white LEDs put out as much, or more 'royal blue' light as any 20k MH bulb without needing to add more royal blues. We (diy'ers) used royal blues years ago because that was the only deep blue LED that came close to mimicking 420nm T5 actinics, but today we have 420nm LEDs, so there is no need to use royal blues as an 'actinic' replacement in my opinion.

How I would build it, I would use 4 meanwell dimmable drivers, put 12x 420nm LEDs on one, 12x cool blues on one, 12x warm whites on one, and then your 4x cyans, 4x reds, and 4x near UV (405-410nm) on one driver. Since near UV/cyan/red LEDs usually only handle up to 700mA, and even that is more than likely too much of those colors, I think it's safe to put all 3 colors on one driver and run it no higher than 500mA (more than likely 350mA will be enough), any more and the cyan color starts to over saturate the color of the water. A little cyan and red color really does make a reef tank 'POP' that much more, so I would recommend those colors for aesthetic reasons. You can certainly add more than 36 LEDs and just dim them down to your liking, I was just saying as far as SPS coral requirements go on your size tank, a 2:1 ratio like you said (I ran that combo for years and it does work), or a 1:1:1 ratio like I said will both provide more than enough light for even the most light demanding corals from my experience.

 

I agree with the not using the 50/50 blue to white ratio. I use a little different approach but I do not have SPS. I use the 445-455nm blue and the 20,000K and 30,000K in my builds. I use a mix of about 30-40% blue to the 60-70% whites (50/50 20,000K/30,000K) I mentioned. I have thought about using some red in my next build I do in a weekend or two. I have the heat sinks and led's now I just need the time. I have a 150G long that has two braces on top so it has three holes on top to set lights. I want to make three fixtures, each having 46-50 led's each with about 40% blue and 60% white but with a couple reds so I thought maybe running 48 led's with the blue/white ratio and adding two 660nm reds to each fixture to make 50 led's for each fixture. I dont plan on having any sps except maybe birds nest anytime soon but if I do I can add more led's to the heatsink very easily. Any thoughts on this ACE?

 

Sorry for the delay, been a busy weekend. To answer the questions in order:

1. Problems with too much 455nm = photo saturation/inhibition in corals, basically, you are giving corals way to much light, to the point the zooxanthallae says 'screw this, we are out of here', then you end up with bleached corals, and if it isn't fixed immediately, end with dead corals in a matter of days.

2. 1:1:1 @ 700mA will be much more efficient, both in providing a better spectrum for corals, as well as longevity of the LEDs. Depending on the heatsink, you may not even need any extra cooling (fans). Once you reach 1000mA (1 amp), LEDs start to really cook, and the extra little output (5-10% more light for 30% more power) isn't efficient at all in regards to power usage on standard 1000mA 3w LEDs. Another plus with the 1:1:1 vs the old 2:1 ratio is you have much greater control over the spectrum and light, meaning it is much easier to make the light aesthetically pleasing while at the same time still providing proper light for corals. With the 2:1, you are limited to turning up/down 1 type of blue, or white, but when you adjust those to match for personal preference, it usually ends up being 'too much' for the corals. That was my mistake early on, trying to make my tank look exactly like a 20k radium with only RB:W, you can do it, but you end up killing the corals with too much blue. This is because a Radium MH has a broad blue spectrum, where as LEDs have very narrow spectrums in the colored LEDs (10nm max). Doing the 1:1:1 ratio will allow you do achieve the 20k MH look, without the killing effect on corals.

3. Kerry: I think 48-50 LEDs for each section in a little too much, especially for not having any high light demanding corals, even birdsnest are what I would consider 'low light' (~100 PAR) even though they are an SPS coral. Basically, once you meet the requirements of the corals, anything extra is just extra $ for the sake of controllability and adding colors for aesthetic reasons. My first light for a 75G cube I went with 48 LEDs, and found out 12 of those LEDs were a complete waste, as I never turn my light up past 50% on any of the 4 channels. Figure each section is about a 50G tank, that would mean you would need 36 LEDs per section. I would still recommend the majority of the blue LEDs be 420nm since that spectrum is usually completely missing in white LED lights and keep the 445-455nm LEDs to a minimum (personally, if I were to add them, I would only add 2-4 out of the 36 LEDs per section).