A different Lighting Question

[StirCrazy]

Originally Posted by midgetwaiter

A label saying "Full Spectrum" is not a good way to judge the spectral output of a bulb, there are no standards for this distinction. It only means that the spectral output is spead across the visual light range. A given bulb may output much more blue or red light than others and still be labled "Full spectrum"

Neither is the kelvin rating. It is mearly a comparison of the overall colour of the output to a reference source that is heated to that temperature. There are also no standards for this rating.

As a matter of fact, spectral output is dependent on many factors, including the ballast. The same bulb will have different output on different ballasts. It will also change over time as the phospor in the bulb ages. Blue output will usually change first as well.

So the answer is, it depends.

you know I am going to have to agree with Bob on this one.. a 10,000K bulb is not a day light bulb but rather a similar spectrum with a heavy dose of blue. even thought the def of full spectrum can vary as a rule any full spectrum bulb will have more than enuf wave lengths in the PAR zone.

Corals use more than just the "Blue" light they also use some of the green and tiny bit of the red. the range of light usable to our corals is 380 to 720 nm, so you can see it includes the blue, all the green and a bit of the red. this light is what people are referring to when they use the term PAR (Photosynthetically Active Radiation) which is the part of the light spectrum that is usable for Photosynthesis. So just because a coral receives filtered blue light in the wild, don't think that it has to have that or even that it will do better with that light. Granted on more intense systems like MH setups you might have to gradually adjust the coral to the new light as a 10000K bulb will throw off way more actinic light and other areas of PAR than a 20000K bulb will, but on a VHO or PC system this shouldn't be a concern.

Steve

[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.

[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

[midgetwaiter]

Originally Posted by StirCrazy

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.

Do you have any references for that?

[Invigor]

Originally Posted by midgetwaiter

Do you have any references for that?

www.reefcentral.com

have at it. I'm sure all the reference you need can be found there. If you want a smaller place to look, http://www.advancedaquarist.com/ is a great site with lots of info.