Originally Posted by CorallineAlgae
Hey shadetreeme, I think that, while these are excellent lights for many tanks, your tank is a bit outside of what these lights are designed to be used for. They certainly don't make a six foot model. Perhaps 4 three foot Ray 2s would work but they aren't designed to be mounted partway over a tank, and in the center where the light fixtures would meet, your tank would have a dark area. I recommend T5s or some other LED system.
I do use a Finnex Ray, and I plan on getting another one for my next build. I'm very impressed with it.
Based on the PAR charts, I don't think there will be any dark areas.
The 48" version has two 24" LED strips yet the PAR on the 48" is significantly above the PAR on the 24." Since they use the same LEDs, the only way this is possible is if there is a decent spread of light off the ends of the fixture.
24" has 192 HO LEDs, 20 watts.
48" has 384 HO LEDs, 39 watts.
I've seen both of these fixtures, the 48" has two 22.5" LED strips and the 24" has one 22.5" LED strip.
If the charts are correct then there is significant light off the ends. There isn't any other way to explain the PAR difference between the two fixtures.
Ditto on the 18" (144 LED, 15w) and 36" (384 LED, 29w). 36" contains 2 of the LED strips that come in the 18" version yet the PAR under center is higher for the 36."
FWIW, I use two 30" and one 24" on my 72" wide 125 gallon. They sit nicely on the glass canopy and they are only about 3" in depth so they are easy to stagger. The unlit 3" at each end of the 30" is a perfect spot to attach moon light LEDs.
Finnex recommends that you do not place the fixture flush on the glass canopy (put the mounting clamps on and then rest the fixture on the canopy).