Will this MH concept work???

Discussion in 'Lighting' started by Jaco Schoeman, 2 Jun 2009.

  1. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    Hey guys.

    Sorry for all the threads, but how else will I get the help I need except by tapping your knowledge...

    Okey, I want to put a 150W MH on the side of my tank, directed from right to left across the length of the tank... The reason for this, is my tank will be dominated by softies and LPS... So I want to place the light living coral SPS , Zoa , RBTA etc right where the MH is, and the softies like mushrooms and chili on the other side of the tank in lower light. Tank size: 1225 x 450 x 450. 10000K MH and two 54W Geisemann T5 Pure Actinic Tubes.

    So will this concept work?

    [​IMG]
     
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  3. Warr7207

    Warr7207

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    It will work, could look quite good, with the change in lighting across the tank.

    You properly end up with quite a narrow, "bright" area as it looks like quite a small reflector you have in the drawing
     
  4. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Thanks Warr. I also think it mught have a nice look to it... The MH I plan to use is this one:

    [​IMG]
     
  5. Tony

    Tony

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    Jaco. I don't think one will be enough as the maximum length that the light would have to penetrate is 1200mm. The light coming from the side only wont help corals a lot especially at the far end of the tank unless you put low light corals there. Why not have two 14000K metal halides at opposite ends facing in and one actinic. This way you will get a better light distribution. Incidently Jaco, Are those the lights for about R400-00 that you were talking about in another thread?
     
  6. trad

    trad Fish, thats the word!

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    I think at the angle you will loose a lot of light, it might look nice with the sun setting kind of effect.

    I would either got for it and not expect to keep light intensive corals or not do it at all. I reckon you'll get about 50% of the light power on the side of the tank you put the light as it is hitting the water at a angle. and about 25% half way.

    I would rather have half the tank with direct mh that could do harder corals and half a tank for softies like two zones in the tank.
     
  7. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    One thing to mention is that I want to keep a chili coral and mushrooms on the "other" end of the tank, so I need very little light there. If I do have to add light there, I will maybe just add two 10000K 24W T5's...
     
  8. Neil H

    Neil H Moderator MASA Contributor

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    why not put a 250 angled like that and a 150 the other side ? sofites will not suffer under the 150 in fact they should do very very well !
     
  9. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Hi guys. Yes, if you read my original post, I do want the section of the tank to have very little light, as I will be keeping non light intense corals there. The section right below the light will house my SPS and LPS . ;)
     
  10. trad

    trad Fish, thats the word!

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    yip i understood but thought it would be better to be more direct and seperate the zones more distinctly
     
  11. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Yes, I hear what you say Trad, and maybe if a tank has different "zones" for keeping different corals it would work AND look great... But it is the Chili coral that all this evolves around... The chili coral needs VERY little light, and I do want one, so thats why I thought that only lighting up one side of the tank and then gradually decreasing the intensity would look nice...

    I think I will just give it a try, see what it looks like, then post some pics for you to judge, and if need be, I'll just add another MH on the other side.

    Thanks for all your input though!!!!

    :thumbup::thumbup::peroni::thumbup::thumbup:
     
  12. crispin

    crispin

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    it sounds like a slightly complicated way to light a tank for one specific coral to be honest. I do like the idea, although its more for the asthetics of having angles light across a tank rather than the advantage of lighting corals.

    why not create a cave efect with the chilli or sun corrals etc (low light specimins) in their, effectivley "protected" or shielded from light and simply light the tank convensionally over the tank. that way light loving corrals and things (nennie) will be better served as well?
     
  13. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Thanks Crispin. Ag, I think as I said, I'll try it and see what happens... If it doesn't work, I'll just plumb another MH in there. I did some further calculations, and it seems that with the CLS (under the brading) the water would only be about 300mm deep!!! Will a 250W MH not be too much, should I rather stick with a 150W on both sides?
     
  14. Manic

    Manic Moderator

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    Just remember you also have to take refraction into account. If the light hits the water at an angle bigger than the critical angle all of the light will just reflect off the surface. You wont actually get any light penetration.

    From quick mind calculations the angle shouldn't be less than anout 40 degrees from the surface of the water to the direction of the light beam.
     
  15. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    VERY TRUE THIS... So in other words, if the angle of light hits the water at less than 40 degrees, it will just bounce off, so at the end of the tank, the light just bounce off the surface, with no penetration... Mmmmm...

    Thanks for that point raised...:biggrin:
     
  16. Reef Maniac

    Reef Maniac MASA Contributor

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    You should consider reflection off the water surface - Most of the light of a MH used normally at 90° to the water surface will penetrate into the water, but light which is shining onto the water surface at an angle will lose some intensity as a percentage of that light will be reflected off the water, and back up towards the canopy. The flatter this angle is, the more light will be lost through reflection, making the lighting very inefficient.

    I would suggest that you rather use 2 x 150W lights on your tank.

    Hennie
     
  17. Reef Maniac

    Reef Maniac MASA Contributor

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    Beaten by Manic :wave2:
     
  18. Manic

    Manic Moderator

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    And also remember that the once the light hits the water it will bend downwards as well. So for example an angle of say 60 degrees hitting the surface will cause the light to travel at 40 degrees in the water.
     
  19. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    But is all this that bad? If the canopy is nice and high, then the light only at the very end would propably be "lost". All light from there back to the source, will increase in intensity. This will be great for the purpose that I plan it for I think, as I can then have my sun coral, chili's etc at the very far end, and then start adding some mushrooms, where the light are a tad more, all the way to the other side where the SPS are kept right under the light...

    Again, I think this will be a nice experiment. Do it, see how it looks, and if need be, just gooi another 150W MH on the "dead" end. No harm done (luckily the tank would be empty when I try this...;))

    IF this works, and works well, I think the effect would be stinning!!! Like the sun rising througout the length of the tank instead of a midday look that will only be on one side for the light loving corals.

    I will update this thread once I've played around with this for sure!!! :thumbup:
     
  20. seank

    seank

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    Also wanted to mention Reflection off the water.
     
  21. jacquesb

    jacquesb Retired Moderator

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