I found this thread very interesting. I wish I had been here from the start.
I am a bit confused about the "flash" of light to kick start the process. Excuse my lack of knowledge about animal systems but I am always trying to convert it to plants (see below) and I guess since zooanthea (sp?) are chlorophyll containing organisms it might apply.
Plant pigments absorb light, as photons, one at a time one per reaction center. The photon carries with it a specific amount of energy required to do a particular job, excite an electron for example. The energy of a photon does not change per se and can be expressed as it's wavelength. If a photon of light in the blue wavelength strikes the specific reaction center it will cause the job to be done, regardless if whether the plant wanted it to or not. If the intensity is low, the PS rate is low, but it still happens and does not need a certain level to start (like double shot espresso in the morning). The intensity does not relate to the amount of energy packed by the photon.
The other thing I am having problems getting my brain around is this Kelvin rating of light. I know kelvin is a measurement of temperature. It can be used to determine the output of an energy source. It can also be used to describe the appearance of the energy source. The sun has a 6500K correlated color temperature.
I found this on the internet (where else??) "Many of you might have heard of the expression "red hot", or seen in films the yellowish colour of molten steel. In fact the hotter an object is, the more it radiates at lower wavelengths. So "blue hot" would be very hot indeed! The sun has a surface temperature of about 5800 Kelvins, which make it somewhat "white hot"." Not sure I get the "white hot" part here, anyway.
Also "cool white" lights have a higher K than "warm" lights.
So a 10000K bulb has a greater range of energy in the red end of the PAR and less in the more energetic blues. Waves in the blues carry more energy than reds.
Does this make sense? The temperature of the bulb in K is really just a description of its spectral output, with its numbers increasing with less energetic PAR or towards the red end, but not intensity (see below).
Sorry I am rambling, trying to make sense out of this.
There are some problems in the words being used in this discussion. As a plant scientist, I deal with light and it's effects on growth.
PAR = Photosynthetically Active Radiation. PAR is measured counting only those wavelengths affecting photosynthesis. Often considered to be anything in the 400-700nm wavelength, however more specifically since photosynthesis doesn’t really occur under all wavelengths, we often only consider those in between the red and blue range (435 - 650).
Intensity = the amount of light striking an object. The further away you are from a 40 watt bulb the less intense the light is. But you are not changing the spectal output of the bulb.
Wattage or output or lumens= is the amount of light generated by the light source. A 40 watt bulb generates 40 watts per meter squared. A 400W bulb will generate 400W of light but the intensity of the light is dependant on the distance from the object to the light. If the 400W bulb were 100' away and the 40W were 2 inches the intensity of the 40W would be higher.
Thus changing my lights to a lower K rating (6500K vs 10000K) will change my spectral output (more blue) but not my intensity.
Thanks for letting me ramble and I appreciate all the work you all put in here.
, now for someone not so picky what would you recommend, lets say hey as long as it isn't too much of any one color visually & I have a verity of corals & my tank is average size?
