"Pszemol" wrote in
:

"Elizabeth Davis" wrote in message
...
Hi, the light setup is the solaris LED
www.solarisled.com

If this is true what they say about PAR output than
it should be ok for seagrasses... as is good for corals.
Acording to the manufacturer it produces more light
than 250W MH. I wonder what is the true spectrum
of the light and if it truly lasts 50 000 hours...


I cannot confirm the PAR or the equivalent lighting output, but the
50,000 hours service time is fairly accurate for LEDs. Note, these may
not have any replaceable parts. Once you reach the end of the lifetime
of the LEDs, the whole fixture will no longer be of use (or, having it
factory reconditioned for another 50,000 hours may come at a cost
closely approaching that of a new LED system).
LEDs will fail in a "full off" manner, meaning unlike the spectral
decay you experience with MH or HO bulbs, you'll get the full power of
the LEDs rught up until the day they die. This is both good and bad.
Good, in that you'll get very consistent light, and an incredibly long
service lifetime. Bad, in that some day when the lights _do_ fail,
you'll have to scurry around for an interim lighting solution, whilst
waiting for your replacement/ reconditioned LED (note, 50,000 hours at
16 hours lighting per day, means you'll have this problem once every 8.5
years, on average.)

Claims of low heat output from hese systems are accurate. The load
demand on a chiller may be significantly reduced.

Spectrum of output is another matter. IME, LEDs emit in very narrow
bands of output, but different band emission LEDs can be "ganged"
together in a single fixture to approximate the spectral output of a
conventional bulb. Does it get close enough to sunlight to make your
corals happy? I'd want empirical evidence to that point, across a broad
range of species, before I'd shell out the extra money for this system,
(and they currently look to be about 2x to 5x more expensive than other
aquarium lighting fixtures . MSRP on 20K 48 inch system; $2325.00, MSRP
on the 72 inch system; $3344 Ouch! Still, for 8.5 _years_ of steady,
bulb-free lighting...).

Again, all of my experience with LEDs comes from industrial use (I work
in an industry which uses UV light to help make chemical reactions
happen; http://www.radtech.org The LED I borrow my experience from is
this one; http://www.phoseon.com/documentation/PHO_RX_Firefly.pdf) , so
this experience may not apply directly to this product.

Regards,
R. David Zopf
Atom Weaver