Do LEDs color shift when dimmed?
- Thread starter Bilk
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blasterman789
New member
The problem with bleaching and LEDs almost certainly has nothing to do with wavelengths other than blue.
The issue is almost certainly due to optics used on LED's, which have no analogy with fluorescent, halide or natural sunlight.
When you collimate a point source and blast that light source onto corals you are causing localized PAR values with no natural adaption. Even wide angle optics on LED's can localize 2x-4x increase of intensity due to law of squares. Now rotate your PAR probe a few degrees and it falls off dramatically. Imagine the skin of corals having to deal with collimating effect. Surface zooxanthellae get blasted while deeper zooxanthellae are in shadow. Agriculture guys laugh off any LED PPFD measurements with any type of optics in use because they are aware of the problem.
Run LEDs sans optics and you have a more typical bleaching scenario as halide per PPFD. Get rid of the otpics and you also get smoother coloration overlaps. Not sure why so many people want disco lights on their tanks.
The issue is almost certainly due to optics used on LED's, which have no analogy with fluorescent, halide or natural sunlight.
When you collimate a point source and blast that light source onto corals you are causing localized PAR values with no natural adaption. Even wide angle optics on LED's can localize 2x-4x increase of intensity due to law of squares. Now rotate your PAR probe a few degrees and it falls off dramatically. Imagine the skin of corals having to deal with collimating effect. Surface zooxanthellae get blasted while deeper zooxanthellae are in shadow. Agriculture guys laugh off any LED PPFD measurements with any type of optics in use because they are aware of the problem.
Run LEDs sans optics and you have a more typical bleaching scenario as halide per PPFD. Get rid of the otpics and you also get smoother coloration overlaps. Not sure why so many people want disco lights on their tanks.
Masterofnonsense
New member
Would using reflectors of optics be a better choice of managing lighting spill and potentially increasing intensity? I seems like it would, as it has been used on halide and fluorescent lighting.
SteelerMike
Member
Run LEDs sans optics and you have a more typical bleaching scenario as halide per PPFD. Get rid of the otpics and you also get smoother coloration overlaps. Not sure why so many people want disco lights on their tanks.[/QUOTE]
So your recomendation would be to run LEDs wihtout lenses and just increase the intensity? Sorry if this is a stupid question. I run 2 Reefbreeder LEDs with 90 degree optics and have been considering removing the optics so I was just curious.
So your recomendation would be to run LEDs wihtout lenses and just increase the intensity? Sorry if this is a stupid question. I run 2 Reefbreeder LEDs with 90 degree optics and have been considering removing the optics so I was just curious.
Bilk
New member
I just received the Buildmyled strips I ordered. They're the Super Actinic Reef Spectrum XB, modified with some violet and UV. Not over the tank yet though. They utilize what looks like a corrugated diffuser over the optics that spread the light. I believe this is supposed to refract the light in multiple directions vs a single point, and eliminate the "disco effect". I guess I'll have to see how the corals respond.
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