Metal Halide

How to: Selecting the Right LED Aquarium Light:

Meaning the way they produce the light isn't that good, the way they reach their wavelength or color isn't that good. Unfortunately as I hate this statement but you get what you pay for.  One huge problem with LED lighting is shadowing due to the light being directed at a max window of 120 degrees this is noticed very little in other lighting due to the light source flooding the tank with light. Another is not being able to spread a certain or multiple temperatures without using multiple LEDs creating the disco effect, Vho and T-5 you can do this, MH not so much as you are limited to a certain range of spectrum but no disco effect.


I do think that LED's are the Reef light of the future whether it be used as a hybrid mixed with T-5's or someone develops a different emitter to allow for a wider spread.  

T-5's were developed in the early 1990's although the technology is based on the T-18 and T-12 lamps. Phosphors are tweaked to give the spectrum desired. Just like any other light source different spectrum lamp were developed for different markets. The German's were way ahead of their time with the development of Phosphors' and made a far superior lamp compared to anybody else.

Here are a few FYI's for you so you can understand why it is so hard for us hobbyist to find information on lighting for aquariums.
With the big manufactures Osram, Phillips, GE, Bridgelux, cree and so on the pet industry accounts for 3% of all lighting products manufactured. Too small of a market segment to specialize in.
Most aquarium lamps and LED's were made for other applications and the specs closely fit our needs and rebadged as aquarium lighting. Most come from the photography and display segments of their market.
There are some small manufactures that custom blend phosphors and manufacture lamps in the spectrum specifically for reef aquariums such a UV lighting international and Interlectric . 
I have not learned of any small companied mass manufacturing specialty LEDs as of yet.

 

I don't have a par meter and am only speaking from my own personal experience.
I had t5's before switching to leds and it was a 4 bulb fixture 48" so 4x54w I'd 216 watts I know have 2 cheap Chinese led fixtures at 120 watts each so 240 watts total... my t5's weren't even close to enough lighting for my tank even for some Lps and definitely not many sps (couple birds nest) at the center, top part of the tank.
Since switching to led that I only run at 50% blues and 30% whites/multi colored so breakdown on that is I'm only using about 100 watts total both fixtures combined? That's half the power I was pushing using t5's at full power obviously and I'm now able to have any Lps or sps in my tank I want and growth rates are great and coloration of corals is ridiculous. So my conclusion on t5 vs led par is that leds push way more par. (especially useable light)
As far as mh is concerned I can't comment on that because I have very little knowledge of mh lighting. I know it's tried and true lighting for a reef tank but it also produces a LOT of heat and consumes a TON of power? I have been told and read that leds push more par then mh per watt? But I don't know 100% so I'm not in a position to back that up.
4 bulb t5 48"fixture 216 watts
2 Chinese led fixtures 240 watts run at 50% blues & 30% white/multi 100 watts and the 100 watts is way more powerful then my t5's even in the shadows of my tank.
I loved my t5's coloration w/ ati bulbs but they just weren't strong enough for my tank needs.
Sorry for the terribly long answer.

After a lot more research I'm finding a lot of people complaining of shadows. Some also say that the pinpoint light source will not allow for good sps colony growth due to shadows .

Can't decide. I love the shimmer from the Kesil. I guess every light source has its pros and cons.. I will not purchase another feature that has a disco ball  or fake shimmer effect... My Acan cost $600.00 for my 29g and I don't like it for that reason

You have been reading articles produced by people who know nothing about lighting. Look outside the tank and read up on PUR and ULE, not on an aquarium website. Another factor what were your old lights?

I think and my opinion is you are use to having T-5 lighting and use to having your whole tank lit up evenly which is LUX and or Lumens. Just because it's bright doesn't mean it's right. You can have a bright tank with a high PAR reading and still have no PUR or ULE. On the other hand you can have a dark tank with low PAR and have high PUR or ULE

Above you state "With my old lights my frog spawn used to be center tank about halfway up in depth(still not enough light) and now with leds I have to put this same coral(frog spawn) on the sides of my tank where it looks like it's shadowed, and it looks better grows better and has better coloration. How do you know it was not getting enough light and in fact may have been getting too much light? Now three things could be at factor here, either your old lights ( I am assuming t-5's ) were at the end of their life or the fixture sucked and the coral was unhappy. The coral was getting too much light in the middle where it was and was un happy ( I would bet one of the two above ) or lastly the LEDs are producing PUR and ULE in the areas which are dark which I doubt but it could be.

Now one comment I want to go back to you made about the dark edges of your tank. I have a Friend with two of the Chinese fixtures above his tank and his fixture sits about four inches from the water and has no issues with dark edges of his tank. I remember you commenting something about you could not lower the lights closer to your tank due to the way you hung them and that the fixture was 9 inches or so off the water. Now is this the fault of the fixture or a fault of how they are hung and the height that they are off the tank?

You are right about Kessil they use a completely different approach how they manufacture their light boards using many diodes, close together, under one lens pretty much eliminating the disco effect. Have you seen the Kessils in person or looking at the pictures on the net? The reason I ask this is I have three people I know who have the Kessils over their tanks. Two like you said look awesome with no dark edges but they still have the coral shading which I think is something that just needs some getting use to. The third tank has the Kessil hung high and the rock looks like the shrine of Israel but the edges of the tank from the botton of the rock work out is dark.

The shadowing people are talking about is under and around their corals not the edges of the tank. MH and T style lighting flood the tank with light, LEDs direct the light down creating more shadowing around the corals.

I really think you need to see many tanks and decide what looks the best for you. Jason I was not beating you up just asking questions and commenting about my experiences.

Have you looked at the kessil site? It is a real neat idea what they did and I can see why they are expensive.