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View Full Version : LED diffuser retrofit?


jrp1588
12/04/2016, 09:47 AM
Watching a couple recent videos from BRS on YouTube, it seems like some LED manufacturers are starting to offer diffusers to aid in color mixing and reduce hotspots. Where I work, we have frosted vinyl that gives glass a frosted look. It would take only a few minutes to apply to the glass of my Reefbreeders fixture. It would certainly be a cheap and easy retrofit. Unfortunately I don't have a par meter to run before and after testing though. Anyone have any thoughts? Would this work optically as well as true frosted glass?

Ron Reefman
12/05/2016, 08:54 AM
three points:

I think the frosted glass will reduce the PAR some, although I'm not sure how much. My best guess having dealt with a big, salty glass center brace, it isn't much.

I don't find my RB fixtures have any 'hot spots' as the leds are so spread out.

Will a diffuser or frosted glass help with blending in the reds & greens which are the major source of the dreaded disco effect? Maybe some. But turning them off or covering them with black tape works even better. And there is more than enough red and green spectrum in the white leds IMHO.

jrp1588
12/05/2016, 09:15 AM
Check out Brs's recent video on the subject. I think par was reduced by 10% or so, but color mixing and disco effect were drastically improved. Without a diffuser, spectrum was all over the place and varied constantly with ripples at the surface. With it, spectrum was much more consistent. I might see if we have some scrap frosted vinyl that I can slap on there for a subjective test

jayball
12/05/2016, 10:52 AM
If you look up diffusion panels or film you will find, typically, between a 10 and 20 % loss of light (from my experience looking, I am sure there are some well outside these numbers). I like the look of diffused LED's personally.

mpierce
12/05/2016, 12:22 PM
https://www.inventables.com/technologies/light-diffuser-films

Used it on a DIY. Good stuff.

zooman72
12/05/2016, 12:59 PM
The Philips CoralCare that BRS tested experienced some 20% loss with the diffuser in place vs when it was taken off IIRC - just something to think about. If one can afford that much loss of PAR, then it might be acceptable to reduce color banding and improve color blending.

One can also simply hang the fixture higher (or remove all secondary diode lenses to possibly achieve the same effect), which also has the added benefit of making servicing easier when the light is always out of the way... :)

jrp1588
12/05/2016, 01:03 PM
I've got loads of free scrap frosted vinyl. I'm going to give it a shot. If need be, I'll turn up my LEDs a bit to compensate if I like the effect.

zooman72
12/05/2016, 01:08 PM
Don't forget to report back with your findings...

jrp1588
12/05/2016, 01:09 PM
Unfortunately without a par meter, my findings are going to be 100% subjective. I'll do what I can though.

jrp1588
12/06/2016, 07:20 AM
Results were a bit disappointing. Install was of course super easy, and only took a minute or so. To my eye, it's cutting the light drastically though. Maybe a less opaque film would be better. As for disco effect, it was slightly reduced, but I've never had it really bad anyway. Color blending wasn't noticeably improved, but again, was never bad in the first place. I did run a sheet of copy paper a few inches below the light with the film on it, and an unmodified light for comparison. It is certainly doing the job, colors blended a lot more smoothly. I just didn't think it was worth the drop in intensity.

HippieSmell
12/06/2016, 09:54 AM
Vinyl probably isn't the best material. I'd look for something made of acrylic or polycarbonate. I briefly tested a cheap acrylic prismatic diffuser from Menards that did OK, and has near 90% transmission according to their website. Makrolon or Makrofol also looks interesting, if you can find it.

jrp1588
12/07/2016, 02:15 PM
Vinyl probably isn't the best material. I'd look for something made of acrylic or polycarbonate. I briefly tested a cheap acrylic prismatic diffuser from Menards that did OK, and has near 90% transmission according to their website. Makrolon or Makrofol also looks interesting, if you can find it.

I think I'm just not going to bother. The reefbreeders lights have a pretty good spread. I will say I did just add a sand bottom to my tank before, where I was previously bare bottom. Now that there's a white sand bottom, the shimmer is somewhat more distracting.

zooman72
12/07/2016, 02:19 PM
Raising the light higher above the aquarium (if you can do it) will help mitigate the shimmer and color separation.

jrp1588
12/07/2016, 02:21 PM
Raising the light higher above the aquarium (if you can do it) will help mitigate the shimmer and color separation.

I'm aware. I HATE all the light spillage though. Plus the glare of looking up at the fixture.