Lighting for growth

Discussion in 'General Discussions and Advice' started by viper357, 26 May 2009.

  1. viper357

    viper357 Admin MASA Contributor

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    Hi Hennie

    Some advice please on using MH lighting for the sole purpose of coral growth.

    I am wanting to use MH lighting to maximise coral growth in a tank so I was thinking of using a lower spectrum MH globe and then supplement with T5's for looks, but would the 20000K T5's not interfere with the MH's?

    I was thinking of either a generic 6500K globe or perhaps the BLV 5200K globe, which one do you think will be better?

    Would there be a noticeable difference in growth rates if using the lower kelvin rating globes?

    Thanks.
     
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  3. Neil H

    Neil H Moderator MASA Contributor

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    tagging along on this one!
     
  4. Tony

    Tony

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    There was a guy on reefkeeping.com that used low spectrum bulbs to get his SPS tank to grow than changed over to blue lights once the tank was where he wanted to colour up the corals and slow down the growth. Here's the link Tank of the Month - July 2008 - Reefkeeping.com
     
  5. viper357

    viper357 Thread Starter Admin MASA Contributor

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    Thanks for the link Tony, this is an interesting comment he made:

    Perhaps instead of using MH lamps, I should think of using 6500k T5's?
     
  6. ziyaadb

    ziyaadb

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    oh yes this is a favorite of many people. Balling method and Bubble king. Hmm what a combination. anyways tagging along
     
  7. Mekaeel

    Mekaeel Moderator MASA Contributor

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    I think Preshan is doing something like this at the moment...
     
  8. preshan

    preshan <img src="/images/ecrccom.gif">

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    yep i am
    i get excellent growth using blv blubs but the tank looks a bit yellow.
    on my previous setup i started with 3 x 150watt mh with 14k blv bulbs and after starting with sps and wanting a higher par i upgraded to 3 x 250watt mh AND used the 2 150watt halides in between.
    i found the 250 watt to really enhanced the colour of the sps corals but
    even with a 250watt directally above some of the sps corals grew towards the 150watt blv halides

    so im now using 250watt blv metal halides for growth and will change back to xm 250watt for colour.
     
  9. Reef Maniac

    Reef Maniac MASA Contributor

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    Good topic :thumbup:

    Coming from a guy who has 3 x 400W MH's on a 1.8m tank, I do believe that MH's will maximise coral growth in a tank, all else being equal. Contrary to the view of the guy quoted in Tony's link stating "An unusual advantage of the T5 lighting is its nature - it illuminates more coral tissue, there is no shade, or shadows", I believe that the MH's "glimmer lines" are actually beneficial in speeding up coral growth. These "glimmer lines" are caused by the MH's point origin light being intensified for short periods by the moving surface water, which acts like a magnifying glass for short periods of time as the water passes between the light and the coral. There has been some studies done which have shown that these short term "bursts" of intense light is beneficial to coral growth, but I will have to trust my memory regarding what I've read, as I unfortunately did not save these publications. What it boils down to is this:

    The zooxanthellae (symbiotic algae living inside the corals) produce more energy under brighter light. They also produce more oxygen which is good up to a point, but at a certain concentration the oxygen actually becomes toxic, and can cause the coral to bleach. The flickering of the glimmer lines increases energy production, but the darker periods in between the high-intensity peaks allow the excess oxygen to dissipate harmlessly out of the coral, rather than build up to the toxic level. In simplistic terms, the glimmer lines thus allows the coral to run at (say) 110% energy production capacity, without burning up, and this can not be matched by any fluorescent light, be it T8 or T5.

    No, I cannot see any reason why they would cause any interference.

    Natural sunlight has a colour temperature of 6500K at the surface of the water. As the light penetrates into the water, it loses some of the red spectrum, which increases the colour temperature. Based on the above, I would guess that the 6500K would be better than the 5200K, but that is only gut feeling.

    As compared with the 10 00K or 20 000K globes? Yes, the 6500K globes should produce the best coral growth. It will also produce the brownest corals, bat that can be adjusted later with specific feedings and water chemistry adjustments, as pointed out in the quoted TOTM article. Of course, just the change in colour temperature allone will make the corals "look" differently, as they would tend to fluoresce under the bluer light.
     
    Last edited: 26 May 2009
    viper357 likes this.
  10. viper357

    viper357 Thread Starter Admin MASA Contributor

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    Thank you very much for the very comprehensive answer Hennie, very interesting information about the oxygen. :thumbup:

    Ok, I will go with the Metal Halide's.

    I now basically have a choice of 2 different Metal Halide globes, either the 5200k BLV or an Iwasaki 6500K globe, the Iwasaki is double the price of the BLV, but if that is going to be the better one then I'd rather go with that.

    This is how I was thinking of running the lights:

    10am - One 20000K T5 on then 30 minutes later all MH's on
    6pm - T5's on for viewing pleasure
    10pm - MH's and T5's off

    I am, however, thinking about doing away with the T5's altogether as this tank will initially be purely for coral growth, not for eye candy :p Once the corals have grown I can then concentrate on colour. But I suppose that's not really such an important issue, I want to concentrate more on the MH's and coral growth right now.

    Will this method of lower kelvin rating lights apply to all corals, LPS, SPS, mushrooms, zoanthids etc. with respect to increased growth?
     
  11. seank

    seank

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    Just buy them Corals Big already:whistling:
     
  12. Reef Maniac

    Reef Maniac MASA Contributor

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    Ja swaer ...
    Yes, it should - but you know how corals are... some of them never read the book, and thus don't know what they are suppose to do :whistling:

    Hennie
     
  13. viper357

    viper357 Thread Starter Admin MASA Contributor

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    Thanks Hennie.
     
  14. DragonReef

    DragonReef

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    And hair algae too ... It looooves the warmer kelvins :razz:
     
  15. Reef Maniac

    Reef Maniac MASA Contributor

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    True...

    Hennie
     
  16. Tony

    Tony

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  17. Reef Maniac

    Reef Maniac MASA Contributor

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    Interesting article - thanks for sharing it with us :thumbup:

    Hennie
     
  18. Tony

    Tony

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    It really made me rethink the more is better attitude to lighting.
     
  19. jacquesb

    jacquesb Retired Moderator

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    WOW! Thanks Tony! VERY VERY Interesting!
     
  20. Tony

    Tony

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    Thanks Jacques. I've cut my halide period from 8.5 hours down to 6.5 hours. They now come on an hour later with an hour off in the middle so the corals can take a breather. The actinics still remian on for 12 hours though
     
  21. viper357

    viper357 Thread Starter Admin MASA Contributor

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    Next question....:)

    I bought some MH pendants, they have 8mm glass shields on them, should I change these to a thinner glass? I'm worried that I might be losing a fair amount of PAR with such thick glass.

    Thank You.
     
    Last edited: 5 Jun 2009
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