STN or Bacterial Infection?

gunit · Jul 25, 2016

A couple weeks ago, a few of my corals started to show what looked like an some form of bacterial infection. It started on my Bali Green slimer and has spread to other corals. It seems to be affecting mostly my SPS, but I did lose a few head of a small Acan colony. I've since lost the slimer, and it seems to be slowly damaging various corals around my tank. Anyone have any idea what this is? Or better yet how I can treat it?

My parameters seem to be mostly inline with the exception of having a bit higher than ideal nitrates...

pH 8.2-8.3
Salinity 1.026
Alk 9 dKH
Ca 420
Mg 1300
Nitrate 13

Tahoe61 · Jul 25, 2016

Do any bubbles develop on brown strands?
It looks like you either have a nutrient and or other water chemistry fish, check flow make sure no power heads have failed or flow is impeded.
What kits are you using to test for alk.

Knapp870 · Jul 25, 2016

I agree it looks like it may be a flow problem. What lights are you using?

gunit · Jul 25, 2016

I haven't seen any bubbles so my assumption was it isn't dino.

My tank is a Reefer Nano with an Vortech MP10 (running about 50% Reef Crest) so I'd be surprised if it was a flow issue. Especially since this is a relatively recent issue and I haven't changed anything in regards to flow. I did have my Firefish pass recently after coming down with a bacterial infection triggered by nipping by my spawning clowns. I caught it a bit too late (as I was away for the weekend) to get him into QT and treat him.

Light is an Ecotech Radion XR15. I use the Hanna checker for Alk, but I can double check it with my backup Salifert.

watchguy123 · Jul 25, 2016

Sps can be so darn ornery. I don't think we know how to differentiate a true sps bacterial or viral infection from good ol STN or RTN. When speaking of bacterial or viral, I'm not speaking of a dinoflagellate break out.

Most problems with sps nonetheless are water quality. And of the most likely for any problem is alkalinity stability. I think that is because if you can keep alkalinity stable, you most likely are doing all the other things with a reef tank correctly.

So assuming your test results are accurate, lots of funky things in the water like TDS or chloramines can cause recession. You seem to have it at both the tips and base. Both chloramines and TDS may be causes. The detective work seems endless but I would most definitely look at how is your water made and if any of the filters are no good. Then looking farther afield, how about Triton for evaluating more parameters than can not readily be tested otherwise.

Curious, "13" is a funny number for a test kit result. Which nitrate test kit are you using.

gunit · Jul 25, 2016

I'll check my TDS coming out of my RODI unit. It could be time to replace my cartridges... Other than that I'd be surprised if it is due to RODI. Only thing that I'm not super religious with drying my skimmer cup after cleaning it, but I'd surprised if that trace amount of tap could cause issues like this.

As for nitrates, I actually got ahold of one of these: http://hannainst.com/products/portable-photometers/hi96728-nitrate-portable-photometer.html . I have used it for quite some time and have always gotten sensible numbers from it. I can't remember if I've cross checked against another test kit in awhile, but I should do that.

Salty1962 · Jul 25, 2016

It looks like your corals are STN or RTN and algae is growing on the dead areas of your corals. Alk swings can cause allot of the issues with SPS. What kind of test kits are you testing your levels with? As mentioned, it could be nutrients. Have you checked your Po4?

pga7602 · Jul 25, 2016

I'm going to say its your nitrate levels. 13 is very high.

How often are you changing water?

rovster · Jul 25, 2016

13 is not high. My guess is alk. Keep in mind SPS may take days to weeks to show any signs of problems after an "event" and can take weeks to months to heal from said event. This makes pinpointing the actual problem difficult and the fact that they continue to decline despite the problem being remedied makes it even more confusing. Best thing to do is check all the likely culprits including test kits, and do everything the way you you know you are supposed to be doing it and try to turn a blind eye to some of that damage because making any drastic changes is the worst thing you can do especially if they are not needed....my 2

saltyfilmfolks · Jul 25, 2016

You can look up arm and rtn articles to differentiate the actual symptoms of a true disease. It's pretty well documented. Many years ago it spread like the flu across the country. And those were the articles I first read on STN.

I would not rule out flow as many of the sticks that do the best in my tank are in flow so high those LPS would shrink and be very very unhappy. With the caveat that all of them do like something different. But if that one is on the sand I'm not sure it's really getting a very high flow.
Fwiw my Params are a bit of a mess and have been for about two months and I am not having problem as like that. Matter of fact I'm having much much better growth and PE.
As your not getting browning I'd say your nutrients are not unacceptably high.
When I do get die off similar to that (slow Stan) I have had different algae and or cyano pretty much immediately appear on the bone and dying flesh. Color and type depends on what's happening in the tank.