Reef Lights - Help with Understanding
- Thread starter RaymondL
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ReefGeezer
Valuable Member
First, let me stipulate that my numbers are not intended to be exact. I'm relying purely on recall.
So... the visible light spectrum (white light) is is made up of photons roughly in the 385 (Violet) to 750 (Red) range. Corals use light in the 385 to about 550 nm range... Violet, Blue, Cyan and a little in the 700+ nm range... red. It is also thought that there is some UV (370-ish) used also. This range is called the Photosynthetic Useable Radiation (PUR). It is a measure of the photons being emitted in the spectrum that many CORALS have evolved to use.
PAR (Photosynthetic Active Radiation) is a measure of all the photons in the visible light spectrum.
Simply put... you need some UV (Kind of a dark violet), more Violet, a whole lot of blue, a little Cyan, and just a touch of Red for most corals. HOWEVER... you might also want some of the yellow and green (roughly 550-650 nm) available because they help with color rendition, particularly of the fish. I doesn't take much though. Too much light above the 500 nm range... even Red... can encourage algae.
Bulbs and LED Diodes put out varying mixtures of photons. It is important to look at the output of each to decide what "Channels" to use based on your desired outcome.
So... the visible light spectrum (white light) is is made up of photons roughly in the 385 (Violet) to 750 (Red) range. Corals use light in the 385 to about 550 nm range... Violet, Blue, Cyan and a little in the 700+ nm range... red. It is also thought that there is some UV (370-ish) used also. This range is called the Photosynthetic Useable Radiation (PUR). It is a measure of the photons being emitted in the spectrum that many CORALS have evolved to use.
PAR (Photosynthetic Active Radiation) is a measure of all the photons in the visible light spectrum.
Simply put... you need some UV (Kind of a dark violet), more Violet, a whole lot of blue, a little Cyan, and just a touch of Red for most corals. HOWEVER... you might also want some of the yellow and green (roughly 550-650 nm) available because they help with color rendition, particularly of the fish. I doesn't take much though. Too much light above the 500 nm range... even Red... can encourage algae.
Bulbs and LED Diodes put out varying mixtures of photons. It is important to look at the output of each to decide what "Channels" to use based on your desired outcome.
PatW
2500 Club Member
There is something called the light absorption spectrum for photosynthetic algae. The main pigments are chlorophyll A and chlorophyll B. Googling the subject and looking at some of the spectra displayed will give you an idea. These use mainly the low frequency light UV, Purple, and Blue with a smaller peak in the red. But there are accessory pigments that capture photon of other frequency and pass the energy on to Chkorophyll A and B. What we are interested in is growing. corals and using a blue and purple dominant fixture works very well. For LED lights, Radions tend to be held in high regard and you can look at the number of LED lights they have at the various wavelengths.
HomebroodExotics
Well-Known Member
all of it is important.
