LED compairison article

[fishoholic]

A must-read if you're evaluating LEDs for your tank!
Feature Article: LED Lighting Tests: Radion, Orphek, Mvava, Ecoray and Ecoxotic

http://www.advancedaquarist.com/2012/1/aafeature

[MarkoD]

Wow look at the light intensity difference between the radion and the ecoray.

[lastlight]

Now I really want some PR156 action!

That MVAVAII sure pumps the light out as well. The cannon-styles seem pretty weak... highly doubt you could replace a 250w halide with one.

[slivermaster08]

After reading a few of his articles a few things pop into my mind: the data is collected through an inverted apparatus with just air and does seem to be corrected for the lack of water.... does that mean these tests are synonamous to having the LED fixture right on top of the water surface? That's what I would infer from these articles. I'm not sure many of us would mount a LED fixture right at water surface for fear of splashes, salt spray and heating up the tank for nano's.


I guess what I'm saying is take the numbers with a grain of salt and don't heavily rely on the PAR levels for picking coral (I was just about to do that because I'm still researching for the right fixture)! I think what the reader should take from these articles is the spread and (relative) intensity comparisons.


A good read and a good find! I'll have to look into these articles in greater detail when I'm not at work. If anyone does read these articles in great detail before me, let me know if the tester included any correction for hanging the fixtures 6-12" above the simulated bottom of tank/measuring point.

[lastlight]

>> LI-192SA underwater cosine corrected sensor calibrated for both air and water

[mseepman]

I think the other thing to remember is that ever since people have been trying to pin PAR numbers on LED lights, they've found that the measurement doesn't seem to represent the results in the same way that it has for MH and T5.

Also, regardless of whether it was right at water level or higher, since they are all compared the same, it just gives you some idea of what you get for the money you spend.

Those Orphek's sure did look pretty at MACNA...haha...but I'm still doing DIY.

[slivermaster08]

Yeah I saw that in his original explanation of the testing procedure but does it state anywhere what the correction corresponds to in regards to how high above the tank the LED would be mounted or does that not matter too much.

For example, does his 24" graph correspond to 24" of water; 18" of water and 6" of air; or 12" of air and 12" of water? I didn't find anything that related to that specifically but I just took a quick read of the articles.

[badAZZlars]

I would have like to see more measurements at 6, 12, 18" so I would know what the mid water corals were getting.

[BigAl07]

One thing to take into consideration Re: PAR - This (in overly simplistic terms) is measuring the light photons striking the sensor. It doesn't measure WHAT type of photon (high in the spectrum, low, etc). So with that being said a MH with say 250 PAR is pretty good but a good portion of that 250 PAR is light that may not be useable by our coral. Look at a spectral graph for MH bulbs and you'll see peaks all over the place (which isn't absolutely bad but not part of this discussion). Now look at LED and see how it's spectral graph is much more defined. So in essence if the LED was putting out the same 250 PAR and it was in the correct spectrum for said coral then it's easy to surmise that more light energy that's useable for our coral is being created by the LED.

Re: Close to the water and heat up the tank for nanos - that's one of the BEAUTIES of LEDs. Their heat isn't projected down into the water from the light source. It comes from the back of the DIODE. Also unless you're using special Infrared LED (which you're not unless you've stuck your TV remote control into the tank) your LED is emitting little to no IR heat. That's why they keep the tank cooler but also why they require a massive heatsink.

[mike31154]

Good to finally see some info on the multi chip arrays. I've decided to go that route with a DIY project & am gathering the parts in the form of 10 watt arrays in royal blue & 10,000K whites. I already have 4 cool white (6,000 to 7,000K) 10 watters with some heat sinks & optics. Work quite well with a 9 volt battery. Not sure whether I'll use optics in the end or not. I have 10 each of the royal blue & 10,000K on the way and figure these should provide adequate spread over my 4 foot tank. If not, I just add a few more. I see that the multi LED arrays now also come in combinations of different colours on the same chip.