What is the difference?

[reefhead]

My LFS had a frag of Green M.Digita setting in a bowl on the bottom of there 180g lite by 3 400w 6500k 14" above the surface.

After I took it home and placed it 6" from my 175w 10k it has basicly lost all color.This also happened to another piece of the same species a few mo. ago.My purple tip acro is growing with great colors.

What is the difference in par/spec? and, is that the cause?

[Bruce]

Reefhead,

There is a phenominal difference in the PAR found in one 400 watt 6.5k compared to the par found in a 175 watt 10k. I believe a 4 fold difference is accurate. I dont have the actual numbers on the PPFD of each bulb, but if you search this forum for Sanjays Spectral Analysis of MH bulbs, the info there speaks for itself.

Now, compound this difference in PAR between one 175 watt 10k, and one 400 watt 6.5k, then remember there were 3 400 watt bulbs over this coral originally. The coral went from extremely intense lighting, to moderate lighting. Give it some time though, as its color may return. As long as it isn't bleaching give it a chance.

I am sure someone will be able to post the link to the Spectral Analysis page that was posted on this board several months ago.

[reefhead]

may point was that the frag was at the bottom of a 180g Tank with the 400w bulb still 14" above the water.

Now, what is the difference in par travling to the distance

[reefhead]

SHOOT!


I need a move to lighting!![img]/ubb/biggrin.gif[/img]:

[Ninong]

OK, I'll move this to the Lighting forum for you. The PPFD (PAR) of a 400w 6500K Iwasaki is 199.7 on an MV ballast (the type recommended by Iwasaki Corp.). The PPFD of a 175w 10,000K Ushio is 63.41 on a magnetic ballast. I have no idea what the actual figures would work out to based on the different distances you are asking about.

There are also significant differences in spectral analysis between these two lamps. The Iwasaki has considerably more energy in the yellow-green band than the Ushio 10K. People who have used both 6500K Iwasakis and 10,000K Ushios report differences in coloration on certain SPS corals.

Ninong [img]/ubb/smile.gif[/img]



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Irrational Exuberance!