Killing coral with too much light

Uwharrie · Mar 14, 2016

I am running Steve's LEDs on a Biocube 29. A couple of weeks ago I ramped up my lights to 60% blue channel and 40% white. everything seemed to be happy until this weekend
My Rainbow Acan bailed, My green lord acan is trying to bail and this morning my poor Hammer let loose and now looks like a green donut.
Water parameters are the same as they have been for 6 months. The only thing that has changed is the lighting settings.
One other thing is the white channel started flickering this weekend. Not just at ramping up and down but throughout the day. I am running a typhoon as a controller

mcarroll · Mar 14, 2016

If you are not measuring with a meter, it's hard to say what light levels you're dealing with.

Get a [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG] (free app for smart phone first, order a $15 handheld for later) and tell us what your peak measurement is.

It seems obvious to say, but I would roll back the lighting changes now.

Uwharrie · Mar 14, 2016

I have a light meter but it reads foot candles. I know I can convert but not sure what level I should strive for?

Triggreef · Mar 14, 2016

I suggest looking elsewhere for causes. If it was caused by to intense light they almost always go pale first if not just totally bleach. Then they pull in and recede from the edges.

I had similar to what your describing happen which I attributed to overdosing iodine, and due to letting copper and zinc unknowingly in through bad ro and tap water through thawing food etc. A triton test might reveal something you can't test for.

Broadfield · Mar 14, 2016

Uwharrie said:
I am running Steve's LEDs on a Biocube 29. A couple of weeks ago I ramped up my lights to 60% blue channel and 40% white. everything seemed to be happy until this weekend
My Rainbow Acan bailed, My green lord acan is trying to bail and this morning my poor Hammer let loose and now looks like a green donut.
Water parameters are the same as they have been for 6 months. The only thing that has changed is the lighting settings.
One other thing is the white channel started flickering this weekend. Not just at ramping up and down but throughout the day. I am running a typhoon as a controller

I also had the same exact problem and it was because of too much light. My Acans and Euphyllias would either bail or the Acans would slowly shrivel to nothing. However, they would always maintain full vibrant color. I struggled with it for 2 years and just assumed it wasn't my lights because nothing ever bleached.

larangcon · Mar 14, 2016

Same here, same story. I had 2 mh fixture with new bulbs, placed my sps higher, figured should color up more but after 2 weeks all the sps I raised up all browned out. I then placed it back in mid-level after a month it all bleached and died one by one.
can't really rush anything in this hobby.

AlexG · Mar 15, 2016

What period of time did it take you to reach that intensity of light and what was the starting intensity?

mcarroll · Mar 15, 2016

Uwharrie said:
I have a light meter but it reads foot candles. I know I can convert but not sure what level I should strive for?

Direct sunlight at sea level is 100,000 lux.

100,000 lux = 10,000 foot candles

A "brightly lit" tank usually has around 40,000-50,000 lux as a peak surface measurement. A reef simulating a surface environment might have up to 80,000 lux, but that intensity will stress a lot of corals. (Which some handle better than others.)

Let us know what reading you take.

Here's one way to do it:

Find the absolute highest peak foot-candle reading you can. It should be directly under the center of the light, but look around and see if there are multiple peaks...not sure how your lights are built, but it's possible.
Once you have the peak, do the math and figure out what 90% of that peak number is. Now take the meter and see how much surface area receives 90% of the peak.
Now measure and see how much area is covered by 50% of peak.
Note where the shadow of your meter falls on the rocks below as you're measuring...that's roughly the area of light you are sampling.

That should give you a really good idea of your lighting coverage.

Don't forget to post your findings!

dacianb · Mar 17, 2016

Corals can handle tons of light without issues, but we have to give them chance to adapt to it. I probably have few times more light than you in tank, but I started low (very low) and increased in tiny steps once at 3-4 days. When I say tiny means 2-3%. Dont measured anything, but leave the corals to tell me when is enough. When I bring new corals I put them in shade on sand and take me weeks to bring them to top.

mcarroll · Mar 18, 2016

dacianb said:
Corals can handle tons of light without issues, but we have to give them chance to adapt to it. I probably have few times more light than you in tank, but I started low (very low) and increased in tiny steps once at 3-4 days. When I say tiny means 2-3%. Dont measured anything, but leave the corals to tell me when is enough. When I bring new corals I put them in shade on sand and take me weeks to bring them to top.

I tend to light corals "as much as necessary" vs "as much as possible", but I do run two tanks right now and one is bright and one is dim...mostly with the same corals doing about equally well in each.

And I'm watching my corals in detail (not unique, most of us do this!) plus using a lux meter (so few do this - it's crazy). Just a different way to doing it - easier on the lights - which will last longer- and electric bill - which is smaller - is all.

It would definitely be interesting to see a catalog of your experiences, as not all corals adapt to lighting stress equally well (or at all, in some cases). Do you specialize in shallow water or lagoon corals, or do you track that level of detail on your stock?

Since you don't measure anything, unfortunately, we can't make as much use of your experience as we might. What light levels are you starting them at? Where do they finish? A [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG] that will take great surface measurements is only $15 delivered, man!

And of course feeding and flow are also primary inputs into how a coral adjusts to stress...so other people's "mileage may vary" as the saying goes.

I basically choose not stress the corals in this way so they have they maximum resilience and ability to heal as they can. Those are the things (so far as science tells me) that are compromised in stressful high-light environments...they literally may have no choice but to grow as fast as they can instead. When another stress comes along, like an injury, they may not heal or they may heal very, very slowly which risks infection. (Just one example.)

sundog101 · Mar 27, 2016

I had a question about lux. I have a kessil a160 and I'm getting about 14000-16000 lux using 2 different phone apps. All my corals seem to be doing well (mixed reef), but based on what I've read this seems pretty low. Do these levels sound right for a kessil?

NanaReefer · Mar 27, 2016

How close to the waters surface did you measure from?

sundog101 · Mar 27, 2016

The measurements are at the surface. The lights about 1 foot above the tank.

NanaReefer · Mar 27, 2016

12" up that sounds about right. Are you running the Kessil at 100%?

Uwharrie · Mar 28, 2016

Since I have a biocube I can only measure with the hood up :-(

mcarroll said:
Direct sunlight at sea level is 100,000 lux.

Find the absolute highest peak foot-candle reading you can. It should be directly under the center of the light, but look around and see if there are multiple peaks...not sure how your lights are built, but it's possible.

Once you have the peak, do the math and figure out what 90% of that peak number is. Now take the meter and see how much surface area receives 90% of the peak.

Now measure and see how much area is covered by 50% of peak.

Note where the shadow of your meter falls on the rocks below as you're measuring...that's roughly the area of light you are sampling.

Don't forget to post your findings!

mcarroll · Mar 28, 2016

sundog101 said:
I had a question about lux. I have a kessil a160 and I'm getting about 14000-16000 lux using 2 different phone apps. All my corals seem to be doing well (mixed reef), but based on what I've read this seems pretty low. Do these levels sound right for a kessil?

They don't publish much info on the original Kessil, so I can't comment much there...but that number is believable given the watts.

I can say that your corals doing fine under about 15,000 lux should be expected. More than that isn't better for any reason that I can see so far on my two tanks where one gets about 14,000 lux and the other around 50,000 lux. Similar stony corals in each.