SPS frag bleaching from the bottom up

[jhatfield]

This is going to be a challenge because I didn't get to grab a photo of this before I left for work. Further, I can't even remember the name of this thing.

This frag has been in the tank about 4 months and consists of three violet colored sticks extending vertically. A few weeks ago it started bleaching or losing tissue from the base of each stalk. After returning from vacation yesterday the bleaching had increased leaving all of one and the bottom half of another bleached. No sign of any bite marks, just an even progression of tissue loss from the bottom upwards.

This is the only sps that is doing this in my tank. The other sps I have are very hardy birdsnest and stylo which are huge; and a couple other newer frags which are growing over the plug. I struggled with ALK/Calcium stability for a couple weeks but for the past two weeks the numbers have been pegged at the readings below.

Alk: 7.9
Cal: 425
Mag: 1310
NO3: 5
Phos: .03
PH: 8.2
Salinity: 1.027 (this was odd. Normally 1.026)
Temp: 77-78

Any guesses?

 

[jhatfield]

Edit: This is a Blue Vermiculata

 

[Dilan Patel]

Jhatfield do some research on STN. From the way you described it sounds more like STN or slow tissue necrosis than bleaching. Whe tissue is being basically pulled off from the base of the skeleton is usually seen as STN.

 

[Luno]

Definitely sounds like stn, something is aggravating it. So many possibilities when it's happened in the past alk stability and phosphate levels particularly leaching phosphate have been on the top of my list!

 

[jhatfield]

Jhatfield do some research on STN. From the way you described it sounds more like STN or slow tissue necrosis than bleaching. Whe tissue is being basically pulled off from the base of the skeleton is usually seen as STN.

Read up a little on STN and I'm leaning towards some sort of contamination. Here are some possible issues:

1. First triton test listed very high chromium and borderline mercury. I found that the metal mount for my LED light was touching the tank water which I reversed. Also did a series of largish water changes since I have no clue how to reduce mercury any other way.
2. I am running GFO possible gfo overdose.
3. Possible contamination from non-food grade RODI plastic storage tank. If it is, this it would explain why the stn accelerated after the water changes.
4. Of course, the couple weeks of fairly large swings in ALK is a prime suspect.

 

[Ostentum]

Alk swings are probably the cause. That will cause tissue necrosis

 

[HB AL]

In my experience it just happens for no good reason once in a while. I usually just let it run its course if it's stn' and it stops on its own, although if it's rtn fragging off the good sections works really well and can save some of the coral left to grow back into a nice little colony. It doesn't happen often and it's always just 1 frag or colony. When it does happen it just leaves me scratching my head, like what the heck. I've come to the conclusion that it's gonna happen at some point, frag the good parts and they remain untouched from it and go on to grow up.

 

[Mal11224]

Your numbers look good. GFO can definitely be the cause. Alk swings can cause it also but that usually comes in the form of RTN depending on the severity. Make sure you are not using too much GFO and make cut back on the amount. Also, do you run a fuge? I used to use GFO months ago and stopped for this very reason (STN). Even my carbon dosing, I use half the recommended for my tank.

 

[jhatfield]

Lots of good info all, much thanks! I went ahead and trimmed the dead parts away and glued the good pieces directly to the rockwork. Will also cut in half the amount of GFO I'm using.