# Light killing Coral!!!



## BKTruong (Jun 29, 2009)

I changed my Coralife 20000k light to a Geiseman 10000k light and my corals are dying!!! What the hell!! Lol... I think the change was too drastic? 10000k is much stronger than 20000k so I guess the corals were shocked?


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## BKTruong (Jun 29, 2009)

I bought the geiseman bulb used, seller said it was only 2 weeks old... If the bulb was really over a year old though it wouldn't kill my corals would it?


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## ameekplec. (May 1, 2008)

it's that you're using a new bulb vs an old one and the output is entirely different. Over time, bulbs (and metal halides are worse than fluorescent) degrade in the quality an quantity of light they put out - so hen changing bulbs it's advisable to do one of several things:

cut down on photoperiod
raise your lights 
add screening o cut down the light and remove layer at a time

Basically, what you need to do is acclimate them to the new brighter light. It will take a few days, but it will prevent future losses.
Give your bleached coral time and care and they should be able to recover if the damage isn't too severe.


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## BKTruong (Jun 29, 2009)

I just changed back to the 20000k old bulb, was too scared to keep the 10000k... should I put the 10000k back in then? The light is the highest it can be as its a hang on light so I guess put it back in and lesson the time to keep it on? My corals are really bleached, it seems only my frogspawns and torch corals were not really affected...


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## BKTruong (Jun 29, 2009)

My Acans took a great hit from the light  Their colors are almost gone...


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## ameekplec. (May 1, 2008)

If the damage i already done, you might as well put in the 10k bulb, raise the fixture and maybe provide a screen (egg crate works). Might as well get them started on the road to recovery.


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## BKTruong (Jun 29, 2009)

I think I'm just gonna keep the bulb changed which is the 20000k until they recover again then switch back but instead like you said I will have it on for a shorter period of time and use egg crating? I will be more aware when I do the change again later on or do you think I should still use the 10000k?


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## hojimoe (Mar 7, 2008)

if you wanted a 10k bulb, there is no point sticking with the 20k after the damage has been done, just put the 10k in, raise as high as you can, add eggcrate as a lid on the tank, and shorten the light period drastically for a few days, and slowly increase it


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## conix67 (Jul 27, 2008)

proper light acclimating can take months!

the lost colors will eventually come back, under optimal lighting condition, so that's not as bad as corals completely dead.. although there shouldn't be any

I found MH very difficult to deal with, especially in a small tank. Just go with T5HO, things are much easier...


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## UnderTheSea (Jun 2, 2008)

Climatizing when you have let your MH go too long can take some time. Raise your fixture if possible, put eggcrate with normal screen to shade the corals or move them lower in the tank. Depending on the quality of bulb they should be changed every 12 months +/- 2 months. Loss of color could also be attributed to lack of blue spectrum in your light.

For our grow tanks we use 10K bulbs but found without supplimenting with actinics the zoa's, ricordea etc lost their colour.


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## advanced reef aquatics (Apr 20, 2009)

if your acans are bleaching check your mg.you may have also shocked them and expelled their zooanthalae.(sp),when changing any bulb start photo period at 4hrs and slowly up to desired photo period.


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## conix67 (Jul 27, 2008)

By the way, why bother with 10000K MH? Do you have a good actinic supplement? Most corals won't look good under 10000K only...


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## ameekplec. (May 1, 2008)

The present RK TOTM is lit by 10Ks, with VHO actinics 

http://reefkeeping.com/joomla/index.php/current-issue/article/25-tank-of-the-month


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## BKTruong (Jun 29, 2009)

so its official guys, some of my corals died the next day actually and the rest are not looking good at all...  Didn't know changes the bulbs could severely damage them thaaat bad... Anyway here's some pics of my set up before they died, I didn't even get to set up the sump yet  Last pic is a pic of my old sump for fun lol


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## conix67 (Jul 27, 2008)

Hmm.. interesting you got a coralife fixture there.. that's what I had too


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## conix67 (Jul 27, 2008)

ameekplec. said:


> The present RK TOTM is lit by 10Ks, with VHO actinics
> 
> http://reefkeeping.com/joomla/index.php/current-issue/article/25-tank-of-the-month


The total wattage on VHO alone exceeds the total wattage of all lights (6bulb T5HO) I have... sweet looking tank, although some photos are definitely enhanced..


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