LED & Bleaaching

[reefgeezer]

I need SPS Guru help...

I have a 75 for which I have built a LED fixture. It consists of 24 3W Cree XR-E that are running @ 1000 ma and 24 Cree 3W Cool White XP-G running @ 1300 ma. They are about 8" above the water's surface. I haven't added any optics. The LEDs are dimmible but I'm currently running them @ 100%.

So... I bought (rescued) a little unidentified Acro that was just a little brown nub glued to a frag plug. I've had it for about 3 months. It has grown well and has good polyp extension particularly when the white lights are off. It has tripled in height and has covered the plug and started to grow onto the rock. I suppose that all sounds good, but the brown coral also became white in just a few weeks and has remained so. The polyps look brown under the white lights and hot pink under the RBs.

The coral is about 14" from the light directly under one of the white LEDs. I'm wondering if this is bleaching or something caused by too much light. Anybody got any ideas?

 

[mike_cmu04]

Sounds like bleaching drop down to 50% and slowly work your way up

 

[lastduke]

I had the same issue before, actually, it is still in the healing process. How long does it take?

 

[sahin]

Recovery, depending on coral and water quality, can take anything from a few weeks to months. Keep up the water quality, feed the fishes well, and keep all paramters stable.

Of course I assume that the light intensity has been reduced first. Once the coral has recovered, then slowly start to increase the light levels.

I wouldnt try to increase the light level before the coral has had a chance to recover first.

 

[westreef]

I don't know if it is bleaching or not. You mentioned it had tremendous growth under led for 3 months and now it got bleached. Usually, the led will bleach it first with no growth at all and then kill it if you don't do anything about it like reduce the intensity or lower the coral to the bottom. This is my two cents.
:uhoh2:

 

[reefgeezer]

I don't know if it is bleaching or not. You mentioned it had tremendous growth under led for 3 months and now it got bleached. Usually, the led will bleach it first with no growth at all and then kill it if you don't do anything about it like reduce the intensity or lower the coral to the bottom. This is my two cents.
:uhoh2:

The coral went from brown to white in a few weeks when I first put it in the tank. I had it down at the bottom to start and moved it up in stages until it got to its home about 14" under the lights in about a month. It has continued to grow and has good polyp extension. Could the thing's natural color actually be white?

 

[bvoss]

I put LEDs on my frag tank. I have tried every spectrum and adjusted the PAR from 150 to 300. Every frag I put in the tank went either brown or white. Today after a year of fiddling, I just hung a 250 watt Radium over the tank. The polyps look better already.

 

[StaghornE]

Those Cree LEDs have alot of light in the red/orange/yellow part of the spectrum. Natural sunlight doesn't have as much. Some corals can't take so much intensity in those colors and it causes them to bleach or die. If you turn down the LEDs and get that spike somewhere around natural sunlight the coral may recover. It's at your discretion to try to raise it again the coral may adapt. I have seen bleached corals grow mainly surviving off nutrients in the water.

 

[westreef]

The coral went from brown to white in a few weeks when I first put it in the tank. I had it down at the bottom to start and moved it up in stages until it got to its home about 14" under the lights in about a month. It has continued to grow and has good polyp extension. Could the thing's natural color actually be white?

Sometimes when the coral has very fast growth, the newly grown tip portion of the coral can be white compared with the rest of the body. This is normal because of fast growth. If the white portion of the coral later on got covered by algae then it is bad. Otherwise, there is nothing to worry about. Could you show us some pictures?

 

[reefgeezer]

Sometimes when the coral has very fast growth, the newly grown tip portion of the coral can be white compared with the rest of the body. This is normal because of fast growth. If the white portion of the coral later on got covered by algae then it is bad. Otherwise, there is nothing to worry about. Could you show us some pictures?

There's definitely no algae growing on it. I haven't been able to get a good picture yet. The white coral and the LEDs really screw with exposure.

 

[StaghornE]

Lower it to a shaded area. Or dim the leds a little It should regain color. I've never seen a white acro even though as stated above new growth is sometimes white.

 

[lastduke]

my experience is. too much LED light 120W switched from 150w MH. SPS was shocked and algae boomed due to the same reason. The SPS was suffered by algae as well. It took me almost 6 month to recover. My LED is still running in 50%

 

[reefgeezer]

I've reduced the blue LEDs to about 85% and the whites to less than 50%. I noticed that the color was more yellow (like 6K) rather than the bluish white (12-14K) I was looking for. We see how that works for a month or two. Thanks everyone.