Revisting halides from leds.

[shred5]

Yes I have these exact issue with mine. I've kept some acros in my QT tank for awhile and this happens to all of them!

What optics?

 

[whixley101]

I have found that putting a substrate or rock underneath that particular coral helps tremendously with this problem. I did not notice the issue until about six months after I changed for MH to LED. I do not have a sand bed so I took a 12x12 piece of acrylic with a two inch lip with substrate in it and placed it under certain corals(acans and acropora mainly) and after about thirty days I notice the growth continued. Once I removed the substrate plate the growth has appears to continue. I am only about sixty days into the "experiment" so I feel like I need another four months to say it actually worked. I am running four AI Vega Color over a 180.

 

[shred5]

I have found that putting a substrate or rock underneath that particular coral helps tremendously with this problem. I did not notice the issue until about six months after I changed for MH to LED. I do not have a sand bed so I took a 12x12 piece of acrylic with a two inch lip with substrate in it and placed it under certain corals(acans and acropora mainly) and after about thirty days I notice the growth continued. Once I removed the substrate plate the growth has appears to continue. I am only about sixty days into the "experiment" so I feel like I need another four months to say it actually worked. I am running four AI Vega Color over a 180.

That is interesting.. It has always been know about white substrate reflecting light back up .. Problem I see is not all corals are close to the substrate.

I really think a wider fixture would make a difference versus a narrow fixture in the middle also tilting the fixture a little. Also having the front leds angled toward the back might help.

Another Idea is a reflector/optics for the front row that only throws the light straight down and back, not forward at all. So basically the frontside of the reflector would be straight down with the back being at about a 60 dgree angle instead of 60 degrees all the way around. We are trying to get light kicked back into the aquarium.. The back row could be the oposite.

 

[ReefLEDLights]

I am not looking at par, No doubt led have enough par. I am interested in the photometrics of the reflector. If the measured par is directly below and it measures higher than another reflector for the same led it probably is not spreading the light out as much. Really is going to be a juggling act to spread the light out without loosing to much par and not wasting to much light either.

What optics are you using on your tank?

Carclo Ripple Wide.

I also know that light is reflected inside the tank, off the sand bed ect.

Back when I was using MH I did have this problem then I improved my flow.

If you really think about it the sun is severe point source say much less than a minute of angle of but moves across the sky. I've seen many coral thrive especially in Cancun were the reef structure will only allow partial direct light. Say 30-40 degrees before the reef structure provides shade.

Bill