What causes STN

[Oldude]

Interesting discussion. For me STN is not that big a problem uless it's a very small coral or it turns to RTN. STN builds reefs in the wild and in many cases in my own reefs it has been a blessing on stags because it seperates the branches into their own individual colonies so in my experience if RTN does set into one of the branches the others don't usually catch it - almost like they didn't receive the "death signal" from the branch that has RTN.
Sometimes I think the cause is that I wasn't holding my tongue right or I looked at it the wrong way - haha. I think we often overlook that what we do in our tanks today may not produce the STN/RTN symptoms for another week or so making it hard to pinpoint a "root cause" especially if we change several things at the same time.

 

[reefwiser]

I think we need to seriously research STN/RTN so we do understand the causes and treatment. So that the hobby can move forward.

 

[Bpb]

For me, almost every time I've had a systemic STN/RTN episode, which is about 3 times now, it always follows an alkalinity episode. Usually an alk spike of some sort, and I'll begin to see the effects of it between 10-14 days later or so. Alk stability has become my no.1 goal in husbandry because of it.

 

[CuzzA]

The cause is stress or damage to a coral which weakens its defense to the bacterial infection and ciliates. Here is the study I posted that Reef Frog mentioned. According to the study, in the wild the bacteria are not present on healthy corals, instead they reside on macro algae. With our closed systems and many refugiums a length of pipe away and a much greater risk of swings in parameters it's safe to assume this is why we see so much more necrosis in our tanks compared to natural reefs.

In the study the cure was a 6 day treatment of ampicillin. This completely haulted the necrosis and the coral remained unaffected.

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[Rodrigo_BG]

For instance- let's say you have a po4 reading of 0.04 , you over use po4 remover and drop it down to 0 within 24 hrs. In my experience this is enough to kick of basal STN due to nutrient bounce . Only use the amount that the manufacturers state , Rowaphos for instance is 100 grams per 400l of water. Plus using too much gfo can temporarily effect ph and pull Alk down a little.

:thumbsup:

 

[acesq]

The cause is stress or damage to a coral which weakens its defense to the bacterial infection and ciliates. Here is the study I posted that Reef Frog mentioned. According to the study, in the wild the bacteria are not present on healthy corals, instead they reside on macro algae. With our closed systems and many refugiums a length of pipe away and a much greater risk of swings in parameters it's safe to assume this is why we see so much more necrosis in our tanks compared to natural reefs.

In the study the cure was a 6 day treatment of ampicillin. This completely haulted the necrosis and the coral remained unaffected.

<iframe src="//www.slideshare.net/slideshow/embed_code/key/wZy9eSpJ7r9ToZ" width="668" height="714" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" style="border:1px solid #CCC; border-width:1px; margin-bottom:5px; max-width: 100%;" allowfullscreen> </iframe> <div style="margin-bottom:5px"> <strong> <a href="//www.slideshare.net/cuzza/white-band-antibiotic-treatment-for-corals" title="White band antibiotic treatment for corals" target="_blank">White band antibiotic treatment for corals</a> </strong> from <strong><a href="//www.slideshare.net/cuzza" target="_blank">cuzza</a></strong> </div>

Thanks for the reference CuzzA, the article is very interesting in shedding light on a cause for STN/RTN that we rarely consider. I am going to try the ampicillin treatment on some SPS that I have that are suffering STN. My parameters are perfect, good flow, good light, other corals are doing well. Perhaps the issue is a bacterial infection.

 

[cugly]

Interesting discussion. For me STN is not that big a problem uless it's a very small coral or it turns to RTN. STN builds reefs in the wild and in many cases in my own reefs it has been a blessing on stags because it seperates the branches into their own individual colonies so in my experience if RTN does set into one of the branches the others don't usually catch it - almost like they didn't receive the "death signal" from the branch that has RTN.
Sometimes I think the cause is that I wasn't holding my tongue right or I looked at it the wrong way - haha. I think we often overlook that what we do in our tanks today may not produce the STN/RTN symptoms for another week or so making it hard to pinpoint a "root cause" especially if we change several things at the same time.

I agree with Greg. If its not an Rtn I try not to over react and cause more problems than what is actually happening