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Discussion Starter · #1 ·
I was in one of my LFSs recently, and they had a nice blue/purple acropora that I'm considering for my tank. My lighting is two 250 watt Iwasakis (6.5k), with three VHO actinics (each 36 inches/ 95 watts).

My question is, should I be able to keep the nice purple/blue color in this coral with the lighting I have? Would this coral likely keep its color better near the top of the tank, mid portion, or nearer the bottom? Tank is 24 inches to the sandbed, and lights are mounted about 10 inches above the water.

Appreciate any help.:)
 

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Discussion Starter · #2 ·
OK, seems I was too simplistic in my question.

I've done some other searches, and found some information and articles written by Eric Borneman and Sanjay Joshi, that suggest that the color temperature of our light systems may have little to do with acroporas maintaining coloration, particularly the blues and purples that are so often sought after. Didn't realize this was such a controversial subject, but their contentions seem to be somewhat hotly debated by experienced hobbyists and their anecdotal evidence/experience of blue and purple acroporas turning brown under 6.5K lighting.

Maybe I should rephrase my question.

How many people who run Iwasaki lights (6.5K), have been able to keep the coloration of blue and purple acroporas? How about people running 10k and 20K lights? :rolleyes:
 

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this is the problem i am having with my acros. they tend to turn brown under my 400w iwasakis. i am thinking i need to add more actinics to suppliment more to bring the K closer to 10k. Casey seems to think if i wait it out the colours will come back. so i am giving it a try. he uses iwasaki's on his tank. he has double the actinics i do though.

G~
 

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Discussion Starter · #5 · (Edited)
Lise:
I just looked at the the purple M. capricornis on your website. Very pretty. Looks like they've all been sold already. :rolleyes:

That seems to be what I've read from other hobbiests, that under 6.5 K lights many see a tendency for the blue and purple sps's to go brown, while others seem to be able to keep the colors under Iwasakis. But in the articles and postings I read from Borneman and Joshi, they seem to say color temperature of the lights is not what makes the coral keep or lose its color, but what you're feeding the corals (or what they're feeding on themselves) is what determines the coloration of the coral for the most part (although they admit they have no idea what you should feed the corals to keep or get that color). But my sense is that in the experience of most hobbiests, the majority see colorful corals go brown under lighting thats predominantly less than 10K.

So, I guess what I'm trying to get a handle on, is whether indeed that is the experience of most people who keep blue and purple sps's (that they have better luck with higher Kelvin lights), and if a significant percentage of people who have them under 6.5k lights have had them go brown. If the answer is that the majority of folks have had them go brown with Iwasakis, I guess I'd pass on getting this otherwise beautiful coral. :(
 

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i do not know exactly what Casey has. he has just said that he uses 2 actinics for each of his iwasakis. so i am guessing he has 500w of iwasakis and 550w of actinics. please Casey let me know if i am wrong. this is on his 100g. this is just what i can figure out from all of his posts.

Rick has 500w of iwasakis and 220w of actinics on his tank he has good colour.

i have 800w of iwasakis and 330w of actinics. i am thinking of adding more.

hth,

G~
 

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I'm running 500W 6500K Hamilton bulbs and 260W PC Actinic and have had no trouble keeping blues and purples in corals. When I was running all PC lighting (520W basically 50/50) and had no prob;lems then either. Actually I fel they had slightly more and deeper colors under the PC's than they do now.

I've had a few discusions with a couple of people and between us and a few others he has talked to, we feel that for growth use the 6500K Iwasakis but to color them up place them under PC or VHO with 50/50 or better/more Actinic.

I have a grow out frag tank with a 250W Iwasaki and 130W PC Actinic. This tank has only been setup for about 3 weeks (it's actually been setup for 6/8 mnonths but has only had lights for about 3 weeks) now but so far the corals areholding color and doing fine.
 

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Discussion Starter · #15 ·
Thanks Lise and Cyberchef.

So maybe actinics are the answer?

Don, I'm pretty close to you in lighting set up with 500 watts total (two 250s) of 6.5k MHs and 285 total watts of actinic VHOs, so thats encouraging that you've had good luck with the purples and blues.
 

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So far it's working for me... :) Of course that main tank with the 2 250W Hamiltons and 260W PC is a 55 and the "newly" setup tank with the single 250W Iwasaki and the 130W PC is about 20 gallons... :) Once I get everything rearranged, had to clean the other frag tank before I could move most of the frags back, I'm going to move the majority of my colonies to the "new" frag tank. It's going to mostly be for grow out of current colonies as well as for grow out of future colonies (I have a few nice frags that are actually getting some nice size to them (although they are still too small to frag) and are going to make nice colonies.
 

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From all I have read I would think color is directly related to the depth from which the coral naturally comes from. I think that's the first question we have to ask ourselves when looking at what type of light is correct for a coral. This is something that seems to make the most sense to me.

As we have all read shallower water is more red/green in the spectrum deeper water filters out the reds and greens and goes to blues. That’s the first consideration.

I would also think that deeper water corals would require less light. If you stick a deep water coral in a bright environment it will take measures to preserve it's self from UV burn.

I really don't see how color is related to light intensity. I really think we worry too much about color. Yes arguments could be made about daylight, and daylight therapy for people who suffer from winter depression and we could also say that corals need light to stay happy.

Ok so now with that in mind I would ask is it really the color of the light or the time of exposure to the light that matters? Please keep in mind that the sun changes in intensity and color as the day goes by. If I recall correctly the sun doesn’t hit " daylight color " till about 3PM. And also keep in mind daylight used to be defined as 50K. I missed the memo someplace where it got changed to 65K.

How do I know all this? I have worked in the electrical and lighting industry for the last 20 years. So what I know and the statements I make are based on that experience.

Ok so back to coral. I would also think that tank raised corals are used to way different conditions then we provide. The frags that are grown commercially are grown in grow out tanks with reflective bottoms and way more exposure to light then we are giving them. For commercial farmers it’s a business and they need to get corals to grow out fast, so they twink. In the meantime you but the coral get it home and it bleaches and dies, small wonder.

It would seem that maybe coral exchanges the like of which I see here i.e. taking frags from other hobbyists is the correct way to go. That would be at least close to the conditions we provide.

My 2c worth

Mike
 

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Discussion Starter · #18 ·
I found this article by Dana Riddle (www.aquarium.net/1298/1298_2.shtml), who at least in 1998 when it looks like this article was wriiten, was convinced that it was light intensity that made the difference in coloration. Although in this sudy it looks to me that he really only compared the coloration of A. nana under varying light intensity, water flow and alkalinity, and kind of dimisses UV effects without making that one of his tested variables (except for green acros). I wonder if he still believes what he wrote in this article?
 
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