Acropora STN

[Labridaedicted]

Hey guys,

I've been having issues over the past week or so with an stn event on my acroporas. One whole large (6" or so) colony has completely died, but now my large ssc colony is doing a similar thing and another is showing similar early symptoms.

To preface, here's my most recent (yesterday) test results:
Phosphates: 27 ppb (hanna ulr checker)
Nitrates: 0 (or close to it using red sea pro low range scale)
Alk: 10 (hanna alk checker)
Calcium: 450 (hanna calcium Checker)
Mag: 1325 (red sea pro titration)
Temp: between 76 and 77 degrees (apex)
Ph: 8.05 to 8.1 (apex)

I notice what appears to be a slime, that I suspect is an algae on the coral before the tissue begins to die as can be seen here.... (this is the one showing symptoms)

These corals recieve strong indirect flow from a gyre 250 which should blast this off and even with manual removal (turkey baster blasting), the stuff comes back in no time (like overnight). Any more flow on them (which i've tried on the first colony that experienced this) and it causes tissue damage, itself. I've observed no parasites and all corals get a dip before introduction.

This is the SSC that's already exhibiting stn and from previous experience, i've got about 2 days until it's a goner......

What's throwing me is that they are exhibiting great color and PE before and even throughout this whole process. Do you guys have any ideas and tips? I've got several other large colonies that are looking great right now and I don't want them to start having the same problems.....

Thanks in advance!

 

[tripdad]

If you can remove them try a dip in an iodine solution. I've had about 30% success rate with it saving STN affected corals. Sometimes it may be bacterial is the thought. Good luck, STN sucks!

 

[blebs]

if that whole colony dies in 2 days thats more like RTN.

clip a frag now, it may be the only chance u get to save any. Ultimately you gotta figure out why it RTN tho..... could be so many reasons.

 

[nashorn]

I would start fragging to save what I can of it. Too many times I have waited too long.
Yea..... to many reasons why.

 

[BoomCorals]

To me an alk of 10 and 0 nitrate and yet phosphate of .08 is not a good combination. I'd lower alk to 7 or 8 over a few days.

 

[Ranjib]

This can be bacteria instead of algae. Slimy, sticky , grows fast ... anything changed recently, any new additions, deletions?
Thanks for the images, they are very helpful

#reefsquad

 

[Crabs McJones]

What lighting do you have under it? You're not blasting them with to much light causing them to bleach are you?

 

[saltyfilmfolks]

I agree with all the above.

Hard to pin point the why it’s happening .

 

[Anirban]

High Alk with that much low nutrient is not a good combination for SPS. In addition if you are blasting them with high light then it can be worse.

 

[reeferfoxx]

Definitely get your nitrates up. The brown stringy algae on the dead coral is a sign that nutrients bottomed out. This happened to me once with the same growth. Dosed nutrients up saved my coral. The high alk increases growth but without nutrients there is nothing to sustain the zoox within the tissue.

 

[jda]

Colonies are hard, whether wild or mari. Even the best-of-the-best lose a good percentage of them.

The tank looks fairly new. New tanks are hard with acropora.

When you blend the two together, even if you did everything right, the success rate would be low.

Edit: I don't like temp at 76, but probably a nit. The rest of your parameters are fine - nobody has zero Nitrate and even very close to zero is hardly a problem unless you are driving it artificially low with organic carbon.

 

[jsker]

Looking at you parameters,
You have 0 nitrates, and high phosphates, and the combined alk.
I would suggest bring down you phosphates with lanthanum chloride dosing to .02 to .03 and dosing urea for bring up the nitrates to 3 to 5 ppm. Let the alk come down slowly.

 

[reeferfoxx]

nobody has zero Nitrate and even very close to zero is hardly a problem unless you are driving it artificially low with organic carbon.

He is running GFO and bio pellets. Actually, he made a good thread on building reactors for the purpose.

 

[jda]

Ok. ...then that can be dangerous and harm acropora.

My N is about .1 and P about .01 and everything thrives. I do not use any GFO, LC or Organic Carbon, though, so I know that I always have some of each of these.

 

[Labridaedicted]

Thanks all! I'll respond to the questions I remember seeing.

The lighting shouldn't be too bad. I'm running 2x an ultra 36" fixtures where the intensity ramps and peaks at about 55% intensity. This is supplemented by 2 6' t5s to get a more even illumination. The 2 specimens pictured here are at about 300-350 PAR as per my apex pmk. Here's my par map...

It seems the general concensus is starving with low nutrients? What is the best way to raise nitrates? I already feed 7 or 8 times daily, so I may need to supplement nitrogen. I took GFO offline while I am seeding biopellets and also took carbon offline.

If it helps, the 2 acros up at around 450 or 500 are the ones that are faring best. I also bumped up my intensity about 3% since this map was done. But slowly, like 1% per week. I estimate my par is at about 375 at the ssc now, but haven't set the pmk up to check for sure. The large colony at 394 par is the other one that already died.

I'll give them a dip this afternoon in case it's bacterial.

Is 27 ppb considered high for phosphates? I thought under 50 ppb was considered the target.

 

[jda]

Take the biopellets, GFO and GAC offline. This will let your tank more naturally figure out what the levels will be. You do not have to do anything else... keep skimming and changing water.

After a few weeks, test the N and P again and see how it trends. As long as you are under 10 N and .1P, I would leave everything also. Some folks like higher numbers, but I do not... especially when I am trying to grow and grow stuff.

A good rule of thumb is to look for a healthy amount of new coralline spots. This is a good litmus that calcification is working well in your tank.

 

[madweazl]

Take the biopellets, GFO and GAC offline. This will let your tank more naturally figure out what the levels will be. You do not have to do anything else... keep skimming and changing water.

After a few weeks, test the N and P again and see how it trends. As long as you are under 10 N and .1P, I would leave everything also. Some folks like higher numbers, but I do not... especially when I am trying to grow and grow stuff.

A good rule of thumb is to look for a healthy amount of new coralline spots. This is a good litmus that calcification is working well in your tank.

I agree with this; makes little sense to dose a source of nutrients or feed more when you have items intended to remove them.

As to your question regarding phosphate levels, 27ppb (.083ppm) isn't a cause for a concern.

 

[hybridazn]

As already stated a few times 0 nitrates and that high of alk is a bad thing. You can try dosing nitrates (feed heavier, use some sort of coral food) or start to lower you alk to at least 8.

 

[reefwiser]

How long have you had these pieces?
The first picture the coral is dead already.
Second the coral is near death.
You can try fragging but from the images you have posted I doubt you will get any surviving frags.

 

[madweazl]

How long have you had these pieces?
The first picture the coral is dead already.
Second the coral is near death.
You can try fragging but from the images you have posted I doubt you will get any surviving frags.

It's the same coral and it isn't dead.

Edit: first two pictures