Metal Halide Lighting

Discussion in 'Lighting' started by shane, 16 Sep 2009.

  1. shane

    shane

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    Hi,
    I have often wondered and ask many people about this lighting issue so I thought to open it up to the people. In a typical lighting canopy, I am not concerned yet about types of corals if the first canopy has 3 150 watt metal halides plus 4 T5 and the second has 2 250 watt metal halides and 4 T5. Both canopies have the same output. The question I would like to know is which of the two canopies will use less electricity? Is it cheaper to run 3 150 watts or 2 250 watts. Does it also depend on the size of the tank, lets say a standard 2 metre tank. Do you get better light distrubition with 3 lights or just the 2?
    Cheers
     
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  3. inflames

    inflames

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    The quick answer is yes. The 3 150watt would use less electricity. Provided the T5 are the same in both units! I would say yes, you would get better light distribution from 3 "light sources" as opposed to 2 "light sources" provided the are evenly spaced. you dont want 3 150watt right next to each other. then you would get better ditribution from the 2 if they are spaced correctly!
     
  4. Mekaeel

    Mekaeel Moderator MASA Contributor

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    3*150W = 450W
    2*250W = 500W
    Shane on a 2 meter tank, I would suggest using nothing less than 4 MH's. I have a 1.8 meter tank with 3*250W MH's, yet the light is not enough. I still feel, if there was one more, it would be perfect.
     
  5. shane

    shane Thread Starter

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    Ok if you were keeping SPS like yourself Mekaeel, then sure 4 would do fine but in the case of someone keeping softies and LPS surely 3 150 watts would be ok?
    To answer your question Inflames, yes both canopies use the same T5 lights.
    Cheers
     
  6. Mekaeel

    Mekaeel Moderator MASA Contributor

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    Im not only talking about SPS Shane. The tank still has some dead spots, especially the ends. Get what I mean? 4*150W MH's on a 2 meter tank with LPS and Softies will work wonders :)
     
  7. Tony

    Tony

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    Four 150 will be perfect but get your tank builder the anticipate this by not placing the bracing over the area where the lights will be and rather in the gaps. This will reduce the light penetration greatly if the bracing is in the srong places
     
  8. shane

    shane Thread Starter

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    So it is agreeable that 3 150 watt MH will be cheaper to run than 2 250 watts, but the more lights I have the better the spread of light over the tank.
    Does this sound correct?
    Cheers
     
  9. Mekaeel

    Mekaeel Moderator MASA Contributor

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    Yes that is correct Shane. But if you want more light penetration, choose lower K rating bulbs and higher wattage's :)
     
  10. inflames

    inflames

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    :thumbup:
     
  11. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    Hey Shane - just my 2c on the subject. I agree with what has been said above, and yes 3x 150W MH would run less electricity than 2x 250W MH's...

    I would recon thought that the Wattage of MH will contribute to the depth it can penetrate. Now if I'm wrong please help me here guys... But if I have a 150W MH at 10000K vs. a 250W MH at 10000K the 250W MH would penetrate deeper than the 150W would. The same would apply to all Kalvin ratings.

    Then just my 2c's on "dead" spots... Personally I like it. They guys who dives would know that water in the ocean is not lit the same everywhere. If you dive behind a drop off, light is less, and there are "dead" spots. The tank I'm am busy with be have scaping to specifically have dead spots, in order for me to keep species like sun coral, chili coral, blue mushrooms, bangai cardinals etc... I say focus your strong light on the coral that needs it, and have your coral that needs less light in the "dead spots" - But that is just me. ;)
     
  12. Andreas

    Andreas

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    I would definately go with 4X150W MH Shane.I currently have 3X150 MH and 4 T5 in my 1.8 and you can see the dead spots on the sides of the tank.
     
  13. Mekaeel

    Mekaeel Moderator MASA Contributor

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    :thumbup:Spot on:thumbup:
     
  14. lIghty

    lIghty

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    Another, more important thing to remember is the PAR of each of the bulbs...

    arguments sake, you may save 50w of electricity by using 3 x 150w, but it may be better to use 2x 250w using 50w more but a higher gain in the PAR rating.... Just something to concider, not sure on the PAR ratings of the bulbs?
     
  15. Mekaeel

    Mekaeel Moderator MASA Contributor

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    PAR is another topic on it own fella. Type of bulb, wattage, brand, K rating......clarity of the water it was tested on.....etc.....
     
  16. lIghty

    lIghty

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    My point is, if you use say 3x 150w bulbs that have a PAR rating of 1000 PAR each = 3000 PAR, where a 250w may have a PAR of 2000 PAR each, therefore = 4000 PAR, for the extra 50w you get an extra 1000 PAR........

    I don't know what the PAR rating of bulbs, I'm just using hyperthetical figures and thinking out the box, I may be totally wrong, maybe a 150w gives a better PAR to Watt ratio than the 250W?
     
  17. Mekaeel

    Mekaeel Moderator MASA Contributor

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    Makes sense.
    But remember a typical MH bulb under a decent reflector covers an area of +- 600*600.
    So we will have to cover that same area whether it is 250W or 150W.
    Dont know if im making sense as my head is sore today :p
     
  18. lIghty

    lIghty

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    LOL,;) I understand you about having a set number lights to cover a area, but I was referring back to Shane's original question about the efficiency of running 3x 150w Vs 2x 250W.
     
  19. shane

    shane Thread Starter

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    Thanks for all the info guys, As always there is a lot to consider.
    I was thinking about redoing my lighting as I currently have 3 150 watt MH's. I have always wandered if it would better (in my case only) to change to perphaps 2 250 watts MH rather than my current 3 150 watts.
    Cheers
     
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