20k 250w MH vs 10k 250MH

Discussion in 'Lighting' started by Ridwaan, 8 Jan 2010.

  1. Ridwaan

    Ridwaan

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    Howzit guys...

    I am in the process of thinking of changing over to 250w MH with some confusion...

    Im a guy that likes the blue effect and Ive heard that some guys are using 250w MH 20k and getting good growth and colouration out of their SPS???

    The ive heard that 20k wont cut it and i need 10k for growth....

    The 20k has a nice effect...:yeahdude:

    Eish, I dunno what to do...Your help will be appreciated..:thumbup:
     
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  3. Sentari

    Sentari

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    Ridwaan are you only running MH's?

    If not change your T5's to actinic lights.
     
  4. Ridwaan

    Ridwaan Thread Starter

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    Im running T5 only.
    Im getting good results from T5s but i think i can achieve better results from MH as my tank is 700mm high....This leading to the T5 penetration issue.

    My only problem is I need to get a chiller when I get MH......issues issues issues, guess we all gotta deal with them sometime..
     
  5. Annoying

    Annoying

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    You don't always need a chiller with metal hallide. I run my tank without a chiller and I have no overheating problem. Metal hallides would be better for the 700 tank as T5's are limited to the penetration. You can also try 14K bulbs they are also very blue and also helps with growth...
     
  6. davidfr7

    davidfr7

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    I got nepturen globes 2 X 15th k and 1 X 20th k. The 20k is not that blue and I find 15th to bright. I bought a peice of LR that was totaly pink MH has bleached in 3 days. My lamps are about 30cm from water line and I put a fan on, I get a 1 deg temp change, with no fan it can jump by 3-4 deg. I don't need a chiller.
     
  7. mnd123

    mnd123

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    Have a look at Adee's tank - he only runs the BLV 20K 250W MHs and the effect is awesome, as is his growth.

    Those BLV 20K's are quite something I must say.
     
  8. Sentari

    Sentari

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    Ridwaan i dont have a chiller. But my tank sometimes jumps to 30. Still need to put a few fans over the ATS. Which should help. However i'm only running one of my 150W MH's.
     
  9. keyaam

    keyaam

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    When planning the lighting on my tank I chatted to a very well known sps keeper and he mentioned that T5s are his preference when it comes to colour and halides for growth depending on K rating as mentioned. So a combination of the two would be best. Another point mentioned was water clarity. T5s will penetrate deeper if the water is crystal clear.
     
  10. Sentari

    Sentari

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    Fully agree with Keyaam.

    10K MH's and a few actinic T5 lights work very well together!
     
  11. mnd123

    mnd123

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    I will only run 250K halides on my 6ft, it is open top and I will move my chiller from my 4ft to it. My 4ft has 6x54W T5's and 2 x 150W MH - it is a closed canopy and I _could_not_ keep the temp down, thus the chiller.

    Must say that since installing the chiller, my inmates are much, much happier, I have less algae growth and my evap is really low, so low in fact that the kalkstirrer is not able to keep up with Ca demand, and I am manually dosing.
     
  12. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    Guys guys guys... We are missing the most important factor here ;)...

    Ridwaan: What corals have you got and what are you planning on keeping? This is the foremost important factor to consider before choosing your MH kalvin rating.

    I have done a hellava lot of research on lighting, and I must agree that 700mm deep would "normally" require MH for best results, again dependtand on what keep under it.

    On my NPS tank, I run two 39W 15000K T5's for about two hours a day. I have some shrooms and zoa's close to the edge of the water at the top of the tank, and believe me they are surviving, but not growing as much as I am used to. Other than that I run Actinic (20000K) and pure actinic for the remainder of the time.

    IMO, if you are not running two MH, one blue and one white, don't JUST have the blue MH - your coral needs more light than that. A nice option to consider is to have your 250W MH in the 20000K but supllement it with 10000K.

    Because of the low wavelength of the blue light, it actually punches the red sepctrum all the way down to the bottom too, which is the primary wavelength requirement photosynthetic purposes. That would still give you the nice blue viewing for the night. BUT, if you keep SPS coral or nennies, supplementing with 10000K might not give you the growth you need.

    So, just think it over VERY carefully, and also your future stocking plans, before making a mistake.

    Good luck... :thumbup:
     
  13. sweetnsour

    sweetnsour

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    very interesting and helpfull topic here guys thanks
     
  14. Ridwaan

    Ridwaan Thread Starter

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    Thanks for the advice guys...

    Jaco, I keep mostly SPS with 1 or two softies and LPS here and there, but mostly SPS..
    Look, I must say, I am getting satisfactory results from T5 only at the moment on my 700mm deep tank...I just think 250w MH would be much much more better..
    Maybe I will go for 2 X 250w MH 14k and supplement with 2 X 54w Actinics. This will give me a taste of both worlds IMHO...
     
  15. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    Yes, that might work well, but again, why so much light? Why not rather go with two 150W MH?

    If you just "gooi" 500W MH lighting in that tank you might sit with a situation where those SPS will bleach, you have to acclimatize them to that sudden bright light... It's like them being 10metres below the water surface and then suddenly being 500m from the water surface in the ocean...

    Go for the 14K MH, yes, and supllement with Actinic, but with mostly SPS I wouldn't go the other way around - unless your feed your coral a lot.
     
  16. Ridwaan

    Ridwaan Thread Starter

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    was thinking of going the 150w route and then i hear from people im gonna w
    ste my time & money using 150w halides..????
    Whats your take on 150w halides?
     
  17. Sentari

    Sentari

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    150W MH's arent a waste of time Ridwaan. They awesome lights!

    I have 150W in mine. But mine is only 450 deep. and the light is about 10-15cm above the water.
     
  18. gaboon

    gaboon

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    You heard correctly, wouldn't go with anything less than 250.
     
  19. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    I'd like to get into a debate with them on that statement... Really...

    There are SO many factors to keep in mind here, that I would need write an article on this. Making a statement like "you are wasting your time on 150W MH's" without taking any other factors into consideration is almost unforgiving.

    Remember that ALL systems are different, and most important factor when it comes to lighting is this: What are you keeping under it, and at what depth. Example: My tank is 2meter deep, so mostly everyone (without a brain) would just say "you must have 400W MH's on that - nothing less". This, without knowing that all my SPS are kept at the very top of the reef, about 20cm from the surface, and that only non-photo corals live at the very bottom... You get my point?

    This again boils down to the point I try to bring forth that we can not generalize. Take YOUR LS and tank into consideration.

    Here is another look at it, and I have said this before: Lighting only comes third after feeding (most important) and flow (second important.) Take this into consideration as well:

    1) Light beams from the sun in the ocean hits waves an angle, which breaks much of the "punch", and only a dimmed version of it gets to the coral tissue. Why do you not tan if you are under water in a swimming pool?

    2) Salt Water blocks out red spectrum light almost immediately

    3) The sun is only 90deg above the water surface for about two hours (11h00 - 13h00) per day, and even then waves are present so only the whitest ripples at the bottom of the ocean are quick bursts of "intense" light.

    4) Zooxanthellae algae can only photosynthesise for about 3hours per day, then any additional light goes to waste. If this light is too strong, the algae will not photo at all. The nutrients corals gain from photosynthesis also doesn't account to 100% of the corals food, it's in actuall fact closer to about 30% max. The coral still has to feed, otherwise polyps would not be needed... This is why feeding is so important, whether it be phytoplankton right up to fish pooh, they still need to eat the rest of the 70% they need.

    So, the point I am trying to make, is that lighting, although an important factor, is not the most important. You really hav to be carefull not to "waste" light, and saying 150W MH is too little is really wasting on a tank of your size. This is wasting energy, and wasting energy kills the environment. Rather feed right, than try and "tan" your corals with light.

    Many will differ from me, but that is my take on it, and I am not saying this just cause this is what I think. Disagree if you like, I'd like to know others' view on this.
     
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  20. mnd123

    mnd123

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    Good advice Jaco, I have 2 x 20K and a 10K in my light unit, but I must say that Adee has awesome colour and growth with the 20K BLV's which "look" closer to the traditional 14-16K MH's - lets see if Adrian weighs into this with his opinion.

    Ridwaan, my tank is 750mm deep as well, and I was actually advised by someone on MASA to go with 400W.... I think thats over kill IMHO, but not sure about 150W
     
  21. Boendoe

    Boendoe

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    Hi Ridwaan, my 2c I have 2x150W 20000K MH, 1x 54w t5 10000K and 1x 54w t5 Arctic. I have a mix of softies, LPS and SPS, and the growth and colours are insane.
     
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