Quote:
|
here is a prime example in One_Divided's tank
|
Steve,
One problem with taking pictures of tanks is that unless both pictures were taken with the exact same camera with it set on manual with its f-stop set at the identical settings and the shutter speed identically, two different digital images can't really be used to represent lighting differences between two different pictures.
Quote:
|
actualy a 175 is brighter.. does it have more PAR.. no
|
So by that statement it appears to me that the Radium puts out more PAR. Which is what the corals use for photosynthesis is it not? Would a sudden(read massive) increase in useable light(PAR) cause the corals to undergo some form of shock? If the corals were to undergo a major shock to the system by a large change in intensity would they not exhibit signs of bleaching?
And I have to ask? are you basing your statement that a 175W is brighter on what your eye sees? If that is the case how does your eye know what is or isn't brighter to a coral? Can you see UV-A? UV-B? Are you able to determine what spectrum of that light being put into that tank will or won't cause problems with a coral?
How else did you determine that the 175W is more intense? Other than the PAR readings that showed the 400W radium was more intense? Lux meter? Spectrum analyzers showing which frequencies are putting out a higher intensity than the others? or just your eyes? I'd say what you are basing the 175W being more "intense" on is that due to the make up of the light frequency (spectrum) of the 10KK, which makes it noticeably whiter in appearance, it is appearing, more intense. This whiteness doesn’t imply that it is more intense. It just means that it is whiter. With the Radiums putting more of the power into the blue wavelengths (which are more difficult (dimmer) for our eyes) if you were to compare a blue light to a much smaller white light, the white will appear "brighter". When in fact it isn't. Being a combination of all the frequencies on a much more balanced scale (intensities of each spectrum mixing with each other out producing the white light). With some reading of the breakdown of visible light by its frequencies you will find that blue is one of the most powerful of the frequencies (as you shift towards purple from red) purple having the most. This is why when you dive into water, as you get deeper it gets bluer and bluer. All other frequencies making up the white light we see above water are being absorbed at a much faster rate due to less power contained.
Sooo.. with that.. A white light may appear more intense.. Mathematically tho. it isn't. Blue is. And thus causing bleaching in Doug's tank due to higher intensity.
Personally after watching corals under various light setups, if I were to see corals bleaching after a change in ballasts and bulbs in a long term existing tank owned by a long term
experienced reef keeper.. I'd tend to agree with him that it was the new radium causing bleaching due to a higher intensity level. Even with all the facts about the make-up of light and how the various frequencies work.
my .02