So last month I had an opportunity to try out a couple of LED light fixtures. Specifically the Radion and a Kessil 350W. I know that both of these lights work great and there are a lot of people who have grown all sorts of stuff under these lights so their effectiveness was not what I was interested in. What I'm really interested in is how they appear to me over my tank. Simply put, how do they look (in my eyes). I have seen a lot of LEDs over tanks at LFS and haven't really been impressed by the light that they cast. Some of them exhibit noticeable discoing effect while many others just seemed dim to me.
What I did was mount each light in the middle of my tank, more or less exactly where my middle metal halide sits and took pictures of them at a fixed exposure setting on my camera. I did this because I was curious to compare the light output of these lights with my metal halide. It is hard to compare light output with your naked eye because our eyes will adjust the light automatically and we have absolutely no control over that. However, with an dSLR camera you can fix the exposure so that the sensor is capturing the same image and amount of light each time.
First up was my 250watt 15K eBay halide.
One thing to note here is that I have some major over hangs, and even so you can still make out some details under them. This is with the halide directly above the middle structure.
Next up is the Kessil 350W. This is the WIDE ANGLE version of the 350. For those who don't know kessils, they are not programmable, but they do have dials on them that allow you to manually adjust the BLUE channel and the WHITE channel LEDs. This picture is with both the blue and white channels maxed out.
My impressions:
1. It's way too blue for my taste.
2. It isn't quite as bright as the halide (but I sorta knew that going into this). I can see that it is a bit darker under the overhangs.
3. It's funny that one of the claims to fame with LEDs is their ability to provide you that shimmer effect that Halides give you. HOWEVER, with this unit I personally found the shimmer to be overbearing. Yes, to my eyes there was way TOO MUCH shimmer. I didn't know that was possible, but sure enough, it was there and very distracting. In fact, if you look at the light as it enters the tank at the top you can see the light rays! I suppose it is possible that over time my eyes would adjust to it and I would just get used to it.
Here is the Kessil 350W again redialed with the blue channel taken down a few notices to try and match the colour temp of the halide.
Impressions:
1. The temperature here is closer to the 15K halide but in order to achieve this I had to knock the blue channel down quite a bit. As a result there is a significant loss of light. It is much dimmer now.
2. The insane shimmering was reduced due to less blue channel being cast.
Finally, here is the Radion unit at full blast mounted in the same spot.
Impressions:
1. The colour temp is more or less the same as the Kessil at full blast. I did not bother to play around with the programming to adjust the colour temperature for the following reasons.
2. Already I could tell that it was dimmer than my halide (again, I kinda knew that going into this).
3. While the shimmering was there it was not as intense as it was with the Kessil.
4. While not annoying and overbearing like with some other units, I could still notice some degree of discoing (separation of LED channels on the sandbed and on some of my lighter coloured corals). I know that a lot of people don't notice the disco with Radions but all of our eyes are different. I can see why some people would not notice it. It's very subtle but I can still notice it (compared to T5s or Halides).
Final Thoughts..
* Both of these lights seem to put out a lot of light. Obviously not as much as Halides, but not everyone needs to blast their tanks with halides. There are people successfully growing SPS under both of these lights so there is enough light there.
* Both lights shimmered as they should but the Kessil had way too much shimmer for some reason. I don't know why.
* I could still see a disco effect with the Radion but not with the Kessil. The Kessil has a much more tightly packed LED array which virtually eliminates this. The Radion's LED array is still far enough apart that I can notice it, but many other people apparently do not.
* I really like the manual adjustability of the Kessil. In searching for a new light we all have different needs. For me, all I really want my light to do is turn on and off. Kind of like with my current light. I can not dim my halides or T5s and I'm OK with that. I don't really need to dim my LEDs either. I don't need lightening storms or programmed cloud cover. I'm fine with just an ON/OFF function for them. As a result of this simplicity the Kessil ends up being MUCH MUCH cheaper than other units with built in computers for programmability.
* And finally, if my halide and T5 combo fixture were to break down today and I was forced to buy a new light I would first try to find a new Halide and T5 combo fixture. However, if I could not, and I was forced to go with LEDs, I would get the
Kessil 350 and possibly add T5 supplementation for dusk and dawn viewing. Thankfully my fixture is still trucking along and I don't really have any issues with it. Sure, replacing bulbs is a bit price in the long run but whatever, I wouldn't be in this hobby if I wasn't prepared to spend some money. The halides do throw a bit of heat into the tank but so long as my central AC unit is working it does a perfectly fine job of cooling the house and the tank down. That in conjunction with fans that I have on the controller have worked out well. Mind you, this may all change if I ever get my hands on a GHL Mitras..