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  1. #1
    Senior Member ReefSalt's Avatar
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    Overkill or what?

    Ok this is the situation,
    I have a 4' DE fixture that is in storage( I thought I would have a Bigger tank) it holds 2 x 250w and 2 x 48"T5`s it is identicle to the unit I have now.

    Right now I am runnig 2 x 250w 10k XM`s w/actinics they are great.Since I have this other unit I was thinking of setting it up with some XM 20K`s well I would stager it 1 x10k and 1 x 20k per fixture.
    That would be 4 x 250w on a 4 foot 125 gl.

    I mean everything is fine in the tank, but I thought it may look even nicer the mix of colors.

    So what do you guys think overkill or ther is no such thing as to much light?
    HTH

    ReefSalt

    Before you buy anything......Read and Research .
    _________________________

    Setup:
    265 gl SPS Reef. AquaScape Marco Rock 150lbs ( Upgrading to a 300gl Deep Dimension)
    Ecotech Radion Pro x 4 & Ecotech ReefLink
    Decante 75g
    Pompe de Remonte PCX55
    Reef Octopus SRO-5000SSS
    Reacteur Sulphur H&S Pour Nitrate
    2x Phosban 550

    Frag Tank:
    Perfect0 45 cube sur le system central
    Totoka LR 50lb
    Radion Gen2
    Vortech MP10W

  2. #2
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    I think that if you are willing to pay for the higher electricity bill, then why not. I have a friend who runs 2x400W and 2x32W PC actinics on his 46G bowfront...

  3. #3
    Senior Member CableGuy's Avatar
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    I say you can never have too much light. Like newguy said if you wanna pay the extra hydro bill why not? Also, I think SPS benifit from a mixture in spectrum. As long as you can keep heat under control, go for it!

    Colby
    "DREAM LIKE YOU'LL LIVE FOREVER, LIVE LIKE YOU'LL DIE TOMMOROW"

  4. #4
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    According to Eric Borneman's Aquarium Corals, you can have too much light. Page 51:

    "The rate of photosynthesis rises in corals with increasing light levels, up to a maximum rate at the so-called saturation level of light."

    "This means that, above a certain level of irradiance, photosynthesis rates will not be increased by higher levels."

    "Coles and Jokiel (1978) also confirmed this in long-term studies with Montipora species, where light levels higher than those to which the corals were normally exposed caused not only reduced growth rates, but also increase coral mortality..."

    "Reduced calcification at very high light intensities was also found by Barnes and Taylor (1973)."

    "The point for coral keepers to remember is simple enough: more light is not always better."

    One method that I use to determine whether I have too much light is with the use of a dissolved oxygen meter. We know that Photosynthesis is "a biochemical process in which plants, green algae, and some bacteria use the energy of light to combine water and carbon dioxide into oxygen and glucose. " http://en.wikipedia.org/wiki/Photosynthesis

    I would measure the dissolved oxygen in my tank after turning on 1 light. After the dissolved oxygen level stabilizes, I would turn on my 2nd light and measure the dissolved oxygen level again. If it increases, then I know my first light did not produce enough light to hit the saturation level. I would wait for the dissolved oxygen level to stabilize and then turn on my 3rd light. If the dissolve oxygen level continues to go up, then I know that my first 2 lights did not produce enough light to hit the saturation level. At this point, I've run out of lights so I can say that having all 3 of my lights turned on produced more photosynthesis then having just 2 of the 3 lights on. If I had more lights and continued the process, there will be a point where turning on an additional light will not increase the dissolved oxygen level in my tank. At that point, I will know that the additional light had no benefit to my tank. Of course, not everyone has a DO meter but there should be scientific instrument stores in most cities that will rent them out.

    By the way, I had a 250W 10K MH, a 96W 50/50PC and a 95W VHO Actinic (441W total) over my 38G when I did my tests and I don't think I hit the light saturation level in my tank even with that amount of light.

  5. #5
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    I did find that the Actinic light produced very little photosynthesis in my tank as the increase in DO was very little when I turned on only the Actinic light.

  6. #6
    Senior Member ReefSalt's Avatar
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    Thanks Guys,

    I read that in Eric`s book but what level of light is to much?If I placed 20K it is in a different wavelenght than the 10K which has a higher PAR.
    HTH

    ReefSalt

    Before you buy anything......Read and Research .
    _________________________

    Setup:
    265 gl SPS Reef. AquaScape Marco Rock 150lbs ( Upgrading to a 300gl Deep Dimension)
    Ecotech Radion Pro x 4 & Ecotech ReefLink
    Decante 75g
    Pompe de Remonte PCX55
    Reef Octopus SRO-5000SSS
    Reacteur Sulphur H&S Pour Nitrate
    2x Phosban 550

    Frag Tank:
    Perfect0 45 cube sur le system central
    Totoka LR 50lb
    Radion Gen2
    Vortech MP10W

  7. #7
    Senior Member Deafboy's Avatar
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    Light levels in aquariums is more than 10 times lower than that at the surface of the sea at noontime in a reefzone. Of course, there's absorption as one gets deeper into the water. If you have SPS or lagoon type corals then I doubt you'd be near saturation levels. In case of animals living in the deep (60 m or more), then I'm not so certain. Either case, I would try it.

    Michel
    20 g reef, 72 g reef

  8. #8
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    Depending on how you look at it, yes it might be somewhat overkill. The difference with in nature and our tanks is that in our tanks, the light is static and does not move..., bombarding the corals in the exact same spot all day long non stop with the same intensity. In nature, the sun moves across the sky each day, lighting more surface area of a coral but not constantly and then there's cloudy days, etc...

  9. #9
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    Originally posted by RobinL

    I read that in Eric`s book but what level of light is to much?

    Well, if you find out that your extra light doesn't produce any added photosynthesis, then its too much in my opinion since the extra light is being wasted.

    If I placed 20K it is in a different wavelenght than the 10K which has a higher PAR.
    Yes, generally, the higher the K, the lower the PAR. See http://www.cnidarianreef.com/lamps.cfm 6500K always had the top 2 PAR measurements in the tests while 20,000K had the least or 2nd least PAR. Also, the ballast can make a slight difference.

  10. #10
    Senior Member ABahn's Avatar
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    I believe there is such a thing as too much light. With my 400W arrangement, I have noticed that some corals (SPS)when place near the surface can get stressed. Believe it or not....BUT, this is a different issue than yours... In your case, as you are sticking with 250s, it may not be all that bad (lower intensity for average spectrum). You would have to try it. If your willing to cram them in there, go for it. You will certainly get an opportunity to blend the light (via mixing bulbs) to your perfection! You have to post pics though!

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