STN at acro tip. Cut? Clean? Pray?

[W1ngz]

I have a strawberry shortecake acro that I recently introduced (2 weeks or so). It hasn't yet found it's groove, and most of the flesh is still a dark purple, with little to no PE.
The flesh from the tip of it has started to recede leaving bare skeleton, and is beginning to be covered in the typical brown-ish algae that comes with that. It's up high in 220-240 ish PAR (seneye) which I'm slowly ramping up to get closer to 300 I hope. It's under a T5/Kessil hybrid.

What's best here?
Cut the tip off just below the receded part.
Brush off the algae to reduce further irritation and hope it recovers.
Burn incense, swirl some tea leaves in a cup and chant something mysterious.

Plenty of softies and some euphylia down lower in the tank, so I keep things a little 'dirtier' than what an SPS dominated tank would have.

0 ammonia, nitrite
10-ish nitrate, maybe 25. Salifert has a really large 'just make a guess' window between those values.
Calcium is a bit high around 470. I've stopped dosing to let it come down below 450.
Alk is 8.6 and stable for months +/- 0.2
Mag is high at 1500. Cut dosing to drop that as well, looking for closer to 1400ish.
Phosphate is 0.09-0.10

 

[Pennywise the Clown]

The standard reply is usually ALK swings but as yours is very stable that is not the problem. As someone who has/is suffering from the same issue I will follow along with interest.

 

[drawman]

Do you have any other acros that are doing well? On paper your numbers look fine.

 

[Leadfooted]

I just lost a colony to STN. I tried to save a few by cutting below the damage as you suggested, all died. I broke the tip off another branch that was only healthy tissue, it's looking great today. That was cut a good bit above where the dead tissue was.

 

[Euphyllia97]

I have had this problem before. My guess is you have had a swing in alkalinity maybe due to the changing of your calcium and mag values without noticing it. I have left the corals the way they were and in the end they started to overgrow the skeleton.

I guess it is a matter of keeping the tank stable and waiting for the coral to start growth again.

Notice the white part on the bottom picture? (Bare skeleton)
First picture is how it looks today as values are stable.

 

[Ifreitas14]

How old is the tank ?

 

[W1ngz]

Thanks for the replies.

Do you have any other acros that are doing well? On paper your numbers look fine.

There are 4 other acro and various monti species that are all slowly acclimating to the tank just fine.

I have had this problem before. My guess is you have had a swing in alkalinity maybe due to the changing of your calcium and mag values without noticing it.

I test Alk 3 times a week, so this is unlikely. Also montipora as you've shown, are much better at re-encrusting dead skeleton than acros.

How old is the tank ?

The contents for the large part, is ~6 years old. The tank itself was upgraded last summer, along with new sand.

 

[W1ngz]

The only other thing I can remember since I got it was during my initial acclimation before being glued down, this particular frag did take a tumble tip-first into the rocks and sand below it, possibly damaging it while it was already stressed from being picked up and moved to my system.

 

[W1ngz]

On the left.

 

[kevensquint]

Also from MTL bud. I would look at bringing your Alk to 7.5-7.8 and keeping it stable, also is there direct flow on that tip, that can wear tissue off too. Your nitrates at 10 or 25 is not ideal. Less than 10 is best. Also the other frags are small, if the tank is relatively young, just that lack of bio aging can somehow negatively impact SPS. These ideas are not necessarily the cause, but by doing what I mentioned, you eliminate those possibilities. Finally I recently came across a surprising video on youtube, not sure yet if I agree or think its a coincidence, but worth a look.

 

[Backreefing]

I always thought dead/burned acropora tips is lighting ( LED burn ) your alkalinity is fine .

 

[W1ngz]

Thanks for the ideas, but I'm not asking for causes I was asking if, when saving the coral itself I was better to cut it below the necrosis or not.

I'll figure it out on my own.

 

[drawman]

I would consider cutting off the top looking at it. If other coral are doing well I sure wouldn't go chasing anything.

 

[Backreefing]

I have had this problem before. My guess is you have had a swing in alkalinity maybe due to the changing of your calcium and mag values without noticing it. I have left the corals the way they were and in the end they started to overgrow the skeleton.

I guess it is a matter of keeping the tank stable and waiting for the coral to start growth again.

Notice the white part on the bottom picture? (Bare skeleton)
First picture is how it looks today as values are stable.

Hi Euphyllia97 if I were you I’d remove that montipora and look under with a lens for MEN. With red is dead and what the heck is these in white. This is how they start

 

[Backreefing]

This is me when I see white dead areas on montipora with little white things near it to LOL
The thread is yours again w1ngz

 

[Euphyllia97]

Hi Euphyllia97 if I were you I’d remove that montipora and look under with a lens for MEN. With red is dead and what the heck is these in white. This is how they start

Yeah that’s what I was saying... that dead part has been growing back. The white parts where just sand particles that landed on there by my goby.

 

[2Wheelsonly]

I wouldn’t go chasing low nutrients as suggested earlier in the thread; your numbers are SLIGHTLY elevated but nothing to worry about. I also think people get too worked up over alk swings. Unless you changed 2.0 or more in 24 hours I wouldn’t worry. My alk typically flucuates .5-1.5 daily and I have never lost sps due to these swings.

flow/lighting would be where I’m looking. Also break that tip off and see if it starts to heal up.

 

[Big E]

Also from MTL bud. I would look at bringing your Alk to 7.5-7.8 and keeping it stable, also is there direct flow on that tip, that can wear tissue off too. Your nitrates at 10 or 25 is not ideal. Less than 10 is best. Also the other frags are small, if the tank is relatively young, just that lack of bio aging can somehow negatively impact SPS. These ideas are not necessarily the cause, but by doing what I mentioned, you eliminate those possibilities. Finally I recently came across a surprising video on youtube, not sure yet if I agree or think its a coincidence, but worth a look.

Interesting, but all I see is that there is philaster in the water, not that they are a cause. Maybe they came along to feast on the already dead tissue as some pods and other animals do once tissue/tips start to die. Heck, my fish will eat dead coral tissue.

From some of the scientific research I've read they are there and do eat the tissue but not sure if they come along later to feast after Vibrio. Mainly in white band disease..........this may be true with any coral losing tissue.

Plucked this from another forum, this seems to have been discussed before. This is one of those chicken/egg type things.

Cure for STN / RTN...Finally!!! | Marine and Reef General Discussion

Got into another debate thread! Cody is the only one debating everything. This thread is not click bait. The picture is accurate and the videos and research are showing the product is working. Of course we don’t know everything which is why everybody is testing. What would I gain by using...

marsh-reef.org

 

[Redfoxtang]

Honestly I think you may be having a testing error and your nutrients are actually low. Usually burnt tips come from alk swings/ low nutrients. I just dealt with this in my tank. Algae growing on tips and I was testing N03 and P04 and was getting readings. Took some water to LFS and I had sky rocketing P04 and 0 N03. Sure enough my test kit was bad. Got my nutrients back on track and let the frags grow over the STN. I did not cut off the dying tissue. Elevated nutrients levels should not cause “Burnt Tips”. Usually elevated nutrients browns out SPS directly. Hope this helps.

 

[W1ngz]

Honestly I think you may be having a testing error and your nutrients are actually low.

My testing on freshly mixed water is in line with Aquaforest's batch ICP test for the box i have and testing against check solutions confirms my kits are good.

That frag is quite tall and has one lateral branch near the base so I'm going to break it up, discard the necrotic bits, dip whats left. Hopefully i end up with at least one viable healthy frag.

Ill have a look at the STN bits under the microscope and see what i can see.