Birdsnest STN from the Bottom Up

[AllSignsPointToFish]

I've been keep green apple and birds of paradise birdsnest for sometime. For nearly as long as I can remember, the green apple birdsnest will grow like craze, then STN from the base. The necrosis never kills the entire coral, but only the top 1-1.5" is alive, leaving a dead skeletal tree underneath.

Any idea what could be going on? Frags from my tank grow like crazy in other people's tanks without the STN, so it must something endemic to my tank. The tank is 4 years old next month.

Temp 76.5-78°F
pH 8.04-8.3
SG 1.026
Ca 450
Mg 1500
dKH 9.6 (my tank has run 9-10 the entire time I've had it)
NO3 1-2 ppm
PO4 0.04-0.08 ppm
K 340 ppm
Fe has always been undetectable
I2 0.06 ppm

I add aminos and carbohydrates 3-4 times per week and dose trace elements weekly.

 

[jda]

This usually happens with point-source lights - ala, Radion, Hydra, MH without Reflectors. There can be other reasons that are more random, but the all stem from just-good-enough health which you would notice with more corals than this one.

If you are using point source lights, this is why lot of folks add T5s to LED or use good reflectors with MH.

 

[AllSignsPointToFish]

This usually happens with point-source lights - ala, Radion, Hydra, MH without Reflectors. There can be other reasons that are more random, but the all stem from just-good-enough health which you would notice with more corals than this one.

If you are using point source lights, this is why lot of folks add T5s to LED or use good reflectors with MH.

I have six Kessils A360WEs with two 60" T5HOs to supplement. Definitely point sources of light on the Kessils. I was hoping it was something other than that, but I can't say you response surprises me.

 

[AllSignsPointToFish]

My friend has a monster colony of this coral. He doesn't use the same lights...he has SB Reef Lights or something similar.

 

[jda]

It probably will help if you use 6500k bulbs in your T5s and run them for like 12 hours - more output and more spectrum than a blue+ or coral+. You can use the Kessils to make the tank as blue as you want to compensate. This is about all that I can offer with what you have and the 6500k might bring out some colors that you have not seen before in some corals.

The other reasons can be from instability where the coral has to "choose" to grow new tissue and let the underside die since it cannot do both. I have seen this in tanks where the N and P are REALLY high, alk fluctuates from 5 to 12 on a whim, temp bounces around, etc... the coral is doing OK and not dying, but not healthy enough to both keep the bottoms alive and also grow new stuff up top. Even with non-point source lights, if you see somebody have a basketball sized colony with no death at the bottom, give them some props for having a stable tank for a long time. Again, if this was it, you would likely be seeing issues from more than just this one coral.

 

[Graffiti Spot]

I normally see it when food or detritus gets lodged inside the birdsnest and causes the coral to die off in spots, then once it starts it can get out of hand. Keeping lots of good random flow is key to helping keep a nice sized and shaped birdsnest. Eventually they shade themselves out and it happens anyways though. Also if algae takes hold in the center it’s always a struggle.
I have never used led and seen the shading but I keep reading it and it makes sense but I would imagine you would see color loss in those areas before death in that instance right?

 

[AllSignsPointToFish]

It probably will help if you use 6500k bulbs in your T5s and run them for like 12 hours - more output and more spectrum than a blue+ or coral+. You can use the Kessils to make the tank as blue as you want to compensate. This is about all that I can offer with what you have and the 6500k might bring out some colors that you have not seen before in some corals.

The other reasons can be from instability where the coral has to "choose" to grow new tissue and let the underside die since it cannot do both. I have seen this in tanks where the N and P are REALLY high, alk fluctuates from 5 to 12 on a whim, temp bounces around, etc... the coral is doing OK and not dying, but not healthy enough to both keep the bottoms alive and also grow new stuff up top. Even with non-point source lights, if you see somebody have a basketball sized colony with no death at the bottom, give them some props for having a stable tank for a long time. Again, if this was it, you would likely be seeing issues from more than just this one coral.

I run a Blue+ and an Actinic on the other bulb. I had been using them only for peak of the day lighting, but I've been increasing the length of time they run in the last few months. I don't really see this on other corals even though they exhibit some muted coloration in the shaded areas (Stylophora, Oculina, etc.). Seems that the birdsnest corals area really prone to this kind of issue.

When I ran metal halide on my last tank (did not have birdsnest corals in that tank), I rank 10K Ushio bulbs. 6500K will seem really white, no?

 

[AllSignsPointToFish]

I normally see it when food or detritus gets lodged inside the birdsnest and causes the coral to die off in spots, then once it starts it can get out of hand. Keeping lots of good random flow is key to helping keep a nice sized and shaped birdsnest. Eventually they shade themselves out and it happens anyways though. Also if algae takes hold in the center it’s always a struggle.
I have never used led and seen the shading but I keep reading it and it makes sense but I would imagine you would see color loss in those areas before death in that instance right?

They're in pretty good flow, and it's fairly random. I have not seen any detritus buildup before the STN starts.

 

[jda]

6500k is yellow, not really white. You don't run it for looks, you run it for output and to color up your corals. I don't really like me a blue or windex tank at all and I don't care for 6500k alone and I do like true 10k and 14k tanks.

In any case, I would run your T5s for as long as you can... they have better spectrum and will cover more areas, so I would let them lift as much as they can and use the Kessils the normal time.