Quote:
Originally Posted by Ron99
Not trying to make a competition out of it, just trying to give some perspective on relative performance of different configurations. As for light requirements for stony corals, that varies widely. LPS generally are lower light, montis would probably be described as moderate to high light and most acros would need high light for best growth and colour. I didn't say you had to have 400 to 500 PAR to grow them but for "optimal" growth and colour my reading has indicated that 400+ PAR is best and as you noted by quoting me from my build thread there is evidence that they photosaturate by 500 PAR so more than that is not really needed. Hence my conclusion that 400 to 500 PAR is optimal. I have a great example in my own tank with a superman monti. My own colony is in the top third of the tank and the base is a nice deep blue colour. I have some frags down on my sand bed and they are growing just fine but the base is a much more pale blue colour. You have only been running this fixture for a month or so. I will be curious to see how everything is doing in 6 to 12 months.
As for my fixture, yes I used 60 degree optics but spaced my LEDs out evenly over the tank so I do not sacrifice spread. I have 4 rows of LEDs, with 3 inches between the rows and the LEDs in the individual rows are 2.25 inches apart. I actually use fewer emitters then the Vertex unit does. I have 80 Cree XR-Es. Vertex uses 128 Luxeon Rebel emitters (pretty good LEDs for the record, equal to or maybe even very slightly better then the XR-Es I used) for their 4 foot fixture. That is 60% more LED emitters but yet it apparently produces less PAR in the tank. I also do not have to hang my fixture higher because of the overlap in the emitters. I can lower it to about 3.5 inches above my water without any major spotlighting or loss of overlap. I currently have it about 5.5 to 6 inches above the water and it is producing the PAR numbers I mentioned at that height.
Basically it is all down to how you configure the LEDs and optics and I guess I do not really understand Vertex's design choice as they could have achieved higher effective output with fewer emitters. Space them out evenly over the tank to get coverage and then choose the number of emitters and spacing between them appropriate for the optics you want to use to produce X PAR at Y depth. Want more PAR for a deeper tank then use more emitters spaced more closely together with tighter optics. Have a shallower tank or don't need really intense light and you can space the LEDs farther apart and use wider optics or even no optics at all for only low light corals or a fairly shallow tank.
I guess that is my point of contention. I question whether the performance justifies the price. Out here in BC that fixture will be $3248 after tax. That's a good chunk of change and 2.5 times what I spent on my DIY fixture.
As for output, his PAR numbers look to be about what I might expect having all the emitters clustered down the center with no optics. High PAR up top and down the center of the tank with a rapid drop off as you go deeper into the water and also as you move to the front or the back of the tank.
As I mentioned before in other threads, I think LEDs are the future of reef lighting but what I see happening is that people will $h1t on LEDs because they spend huge amounts of money on a fixture then eventually complain that the performance relative to their 250W or 400W MH is poor and that LEDs are no good for reef lighting. It taints LEDs in general when it was really down to the design of the particular fixture.
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Thanks for your input Ron. I am interested in other peoples opinions and perspectives on LEDs as they are still a very new technology. I unfortunately do not have a big budget on my reef project. Therefore, equipment choice is crucial that it be money well spent. I am actually more leaning towards the Maxspect LEDs with the optics included. Although, I do like how Vertex has some cool features such as the clouds and lightning but I feel I would tire of that easily and doubt it would be used in the long run. The programmable computer option is very interesting as well and seems quite convenient. I think I will wait one more month and let the dust settle from MACNA before finalizing my decision.