400w Halides

Discussion in 'Metal Halide Aquarium Lighting' started by Elliot09, Jul 13, 2010.

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  1. Elliot09

    Elliot09 Bristle Worm

    Joined:
    Aug 26, 2009
    Messages:
    149
    Hey all

    I currently run two 150W halides on my reef tank, and I keep a few SPS colonies. SPS are near to the top, certainly no lower than the middle. I don't seem to get very good SPS colour, growth and polyp extension is fine, but mostly, they're brown.

    My params are a pretty constant:

    Mg - 1400 ppm
    Ca - 450 ppm
    KH - 8 - 9
    NO3 - between 1 and 3, depending on water changes.
    PO4 - always undetectable

    Running carbon and a phosphate remover, and I've got good flow.

    Conditions are pretty good, I just feel that my lighting may not quite be enough.

    I've found a second hand Arcadia 2 x 400w fixture that's a very good price, and I'm definitely considering it - do you guys think that this will make a big difference on my colouration? Ideally, I'd like to go 80-90% SPS, with just a few LPS in the long run, so high PAR at a decent depth is quite important, too. I know about light acclimation to make sure I don't bleach out my corals when I step up the lighting, as its a big step up, i'd do it gradually and carefully.

    Basically, what I'm asking is, do you sps geniuses :p think that this upgrade would be a good move?
     
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  3. steve wright

    steve wright Super Moderator

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    shenzhen Guangdong PRC
    how deep is your tank Elliot?

    if its very shallow , you may have problems with heat
    and you may have to have it a lot higher than would be normal

    but I have seen good results (amcarrig's 90 gallon tank which I assume is 18 - 22 inches deep) and that runs using 3 x 400 watt MH lamps

    find the thread
    check out the colours!

    IMO provided your cautious with the light acclimation - very high and bring down slowly over a period of weeks and not days

    then this upgrade will certainly help to improve the coral colours

    NB if you run supplemental T5 actinics - leave them on a couple of hours extra each day
    that helps with any blue and purple SPS - IME

    Steve
     
  4. Elliot09

    Elliot09 Bristle Worm

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    My tank's 24" deep - how far off the surface would you think that the lights should be, Steve?

    Cheers for your help!
     
  5. steve wright

    steve wright Super Moderator

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    IMO
    10 - 12 inches above water surface eventually Elliot - some go as low as 8 , but you can get temp issues and it also makes working in the tank difficult without burning your arms

    as your upgrading from 150s - I would start at 20 inches above water surface and lower by 1 inch each week for 8 weeks until you reach 12 (pendants on chains where always ideal for this as lowering by 2 links each week was how I did it in the past)

    also reducing the amount of time there are on during this period will help with the adjustment

    if your currently at 10 hours with the 150s - Id drop down to 6 hours for the 1st 4 weeks (at the new raised height)
    8 hours for the 2nd month and then leave it at 8 for a few more weeks once the lights are at the 12 inch above water level height

    Steve
     
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  6. Elliot09

    Elliot09 Bristle Worm

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    Thanks for your help again, Steve. Will try and get my hands on the lights ASAP and let you know how it goes.
     
  7. Night-Rida

    Night-Rida Finback Whale

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    Tampa, FL
    sounds like whats steve said! lol