Has anyone run into Light Induced STN?

T

troublemaker

Member
I'm having a weird issue with a few frags and have exhausted most other places to look, so I'm looking at things that don't exactly make sense.

I have a few frags that have started to STN in rather strange ways. One has receded back everywhere at the base except for the part that is shaded by the branch, it's actually growing perfectly in the branches shadow. The other two that are doing it aren't exactly as easy to figure out, but both have started receding on the part pointing toward the light.

Is this even possible?
 
ColaAddict

ColaAddict

New member
Is it STN or bleaching. STN means dead tissue. Never heard I light causing STN.


Sent from my iPhone using Tapatalk
 
Paulip

Paulip

New member
If the shaded part stands out, then lighting is a factor (possibly in combination with something else). Maybe it is some algal growth on the lit part.

How are the phosphates?
Are you running adequate flow for the coral to clean itself/stay clean? Does this coral have a self cleaning mechanism like leathers?
Any changes in the lighting? Running unusual spectrums?
 
tinman

tinman

Well-known member
Light can indeed be a factor but it would bleach and then stn ..

It goes like this imo

Low nutrients == low alk == low light
Higher nutrients == low or high alk is ok = corals can take higher light




Sent from my iPhone
 
T

troublemaker

Member
I will try to get a picture, but the tissue is dead, not bleached. I agree that it's probably a cocktail of factors, but light is definitely involved.

Parameters
1.026
Alk 8
Cal 450
Mag 1400
Nitrates 10-15
Phosphates undetectable, but with the fuge and basketball of Chaeto it always going to read 0, even if it isn't.

Flow is 2 Gyre 130s, it's enough to lose some skin on close across and make bare spots everywhere.

I did change the settings on the Radions but I went to a bluer spectrum and lowered intensity about a month ago. This all seemed to start when I went to the wide angle Lenses on the Radions which I figured would decrease the PAR also.

Everything about the lighting should be ruling itself out, but the fact the coral still looks good in the shade leads me to think it's still the issue, even though common sense would dictate it isn't.
 
SkullV

SkullV

New member
What intensity are the radions running? Try killing the red channel 100% as well. Are the frags having issues directly under led pucks or far away?
 
T

troublemaker

Member
SkullV said:
What intensity are the radions running? Try killing the red channel 100% as well. Are the frags having issues directly under led pucks or far away?
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I am running the 14k setting at 60%. The frags that are having the issues are about 4" off the sand bed. The lights are hung 9" off a 16" tank so they are about 20" from the light and slightly off center.
 
tinman

tinman

Well-known member
troublemaker said:
I am running the 14k setting at 60%. The frags that are having the issues are about 4" off the sand bed. The lights are hung 9" off a 16" tank so they are about 20" from the light and slightly off center.
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i dont think thats light induced ..i run my radion g3 pros at 14k and 80% for 2 hours in the peak and then 20k and 80% 2 hours before and after that .. thats 6 hours total at 80% and then another 3 hours of only blues at 100% before they turn off and thats with regular lens ( not wide angle)

unless your nutrient levels are very very low and in that case .. 60% at 14k is very harsh for them if not properly acclimated.
 
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T

troublemaker

Member
I wont argue with you, I am more than willing to explore any avenue right now. But if you look at the picture, it's hard to dispute the fact that what is in the light is dead and what is in the shade is alive.
 
tinman

tinman

Well-known member
troublemaker said:
I wont argue with you, I am more than willing to explore any avenue right now. But if you look at the picture, it's hard to dispute the fact that what is in the light is dead and what is in the shade is alive.
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again i stick to my theory :)

if you have less nutrients corals need ( and will accept lesser light)

if you have more nutrients corals will accept higher light.

my tank i assume is far from ULNS .. but if yours is ULNS then lower light and lower alk is the way to go.



PS : i cant see the pic on my work network :( and phone wont show much detail ..
 
T

troublemaker

Member
tinman said:
again i stick to my theory :)

if you have less nutrients corals need ( and will accept lesser light)

if you have more nutrients corals will accept higher light.

my tank i assume is far from ULNS .. but if yours is ULNS then lower light and lower alk is the way to go.



PS : i cant see the pic on my work network :( and phone wont show much detail ..
Click to expand...
I have no trouble with theories at this point. If you get a chance to view the picture it might explain my ramblings in a way I am not able to get across.

My tank is far from low nutrients, I feed very heavy, but export heavy also. Nitrates are always above 10.
 
Paulip

Paulip

New member
A lot of things are fixed by big water changes.

It's like the "reboot" in the technical support field.
 
Venom

Venom

Premium member
This happen to me when I had a Alk spike it went from 9.0 to 11.5, with sps you can't rule out anything.
 
T

troublemaker

Member
Paulip said:
A lot of things are fixed by big water changes.

It's like the "reboot" in the technical support field.
Click to expand...
I agree, I have changed out 300 gallons of water through 10 water changes in the last month. The tank has never looked better, except for these few frags. There are about 60 other SPS frags that all look great.

I am not going to rule out Alk swings, I have to tweak my Kalk reactor almost weekly now, it has been as high as 9 and as low as 7.5.
 
Paulip

Paulip

New member
troublemaker said:
I agree, I have changed out 300 gallons of water through 10 water changes in the last month. The tank has never looked better, except for these few frags. There are about 60 other SPS frags that all look great.

I am not going to rule out Alk swings, I have to tweak my Kalk reactor almost weekly now, it has been as high as 9 and as low as 7.5.
Click to expand...
Yikes. How about volunteering a frag for a dip? You might be surprised what pops out.
 
T

troublemaker

Member
The frags were cut and dipped this evening. We will see how it goes. I don't want to alter too much at this point since the rest of the corals are doing fine.
 
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