[StirCrazy]

Originally Posted by midgetwaiter

I don't disagree with anything that Stinky has said but what we have to remeber is that not all animals have the same requirements.

Some bulbs will provide more PAR in the blue range, in certain situations this may be required or at the very least provide different results.

Can anyone defend the idea that all corals have the same light requirements? You can't possibly know if this will work as well or better in any particular situation, there are too many factors.

actually ya, there are several lighting experiments that support this done by scientists and such. at any rate the only time there is a problem is when you give deep water corals to much light to fast. from my own experience I bought a deep water acro and over the course of two months I moved it from the bottom of my tank (shadows) to the top (full light) and it did amazing, the problem comes in when we buy such a coral the day it arrives from overseas and plop it directly into our tanks in full light. another thing to note, I can take my PAR meter outside and hit about 1500 units on a sunny day, you get about 2000 units in the tropics, but yet my tank only produces 800 to 880 units at 12" (8" under the water, and this is on the high end of most setups) so you can see almost all of us with MH systems are pushing less than 1/2 of the natural light strength they are used to in the first place, now if you go down to a 96 watt PC set up you are looking at numbers around 300 units, but a 10000K type bulb does have a large spike in your "actinic" range but has the added benefit of green light and a bit of red to alter the color. it is not necessarily the color of light that the corals, rather the algae in the coral rely on but the range of wave length and the intensity, so if all light as mentioned between 380nm and 720nm will cause photosynthesis, then the coral will expel or attract algae to have the proper number for the light available. this take time and if you slowly expose your corals to more light over time you will not have a problem but if you slam the light to it then the coral will expel a massive amount of algae and we get what we call bleaching as it over reacts because of the excess sugars produced so rapidly.

Steve